Version 2 Changes: 
ALL SHELL TYPES ARE MERGED INTO ONE.
I changed it so it's easier to balance out.
First of all, shell types now has 4 shells (5 with cap boost)

Shelling changes:
All Uncharged shell damage from each type is now equal to wide's uncharged shell damage/elemental/stun/exhaust.
All Charged shell damage from each type is now equal to long's charged shell damage/elemental/stun/exhaust.
All burst shell damage from each type is now equal to normal's burst shell damage/elemental/stun/exhaust.

I then reduced all shell damage by 10%
Elemental scaling got reduced too by .25(uncharged/charged) and .5 (burst/wyvernfire) - look at wyrmstake rework below to make up for it

Since shells got reworked to be all the same on all shell types all stun/exh values has been reworked too like this:
half of value of swordphial/normalphial/aedphial/saedphial is put into unchargedshell/chargedshell/burstshell/wyvernfire respectively because stunning/exhausting values were too weak.

***NEW***

WYRMSTAKE changes:

-Wyrmstake explosions triggered from shellings is now reverted back to it's original value.
-Wyrmstake explosions triggered from (uncharged/charged) now has .25 elemental scaling and explosions triggered from (burst/wyvernfire) .5 elemental scaling.
-Wyrmstake explosions triggered from (uncharged/charged/burst/wyvernfire) now has half of stun/exhaust value from phials.

I wanted wyrmstake to be rewarding if you play well and put it on a good spot on the monster.
Since shells elemental scaling is reduced this is where those values are put, same goes with stun/exhaust values.
So if you want to deal good elemental damage -> try to put it on a monster's weakest elemental spot.
And if you want to stun faster try to put it on the head.
In other words, the remaining values is on wyrmstake so you pretty much have the full value of all phials:shell with wymstake explosions that is if you put it on the right spot.

NOTE: In terms of balance on this version, this is waaaay better and after some testing I must say that this is in a good spot. 
However, if you feel something to be too weak or too strong tell me.


-------------------------------------------------------------------------------------OLD VERSION,SOME CHANGES KEPT----------------------------------------------------------------------------------

I tried it with defender set which has wide and only used uncharged shelling which proc'd blast (once) after a while(1min before death on LR tobi).

In terms of stunning/exhausting. I have stunned a monster once at average on a decent time and twice on lower tier monsters but they are dead atleast a minute after the second stun. 

As far as testing status buildup(blast/poison,etc and stun/exhaust) it seemed pretty fair as if it was natural.

Shelling WAS stuck at fire damage that's why it didn't use any  elements(which I removed and it now applies element/status buildup)  HOWEVER fire element up did not affect it. So with these changes I have no clue if element up has any effect NOW on said weapon element on shelling. 
So if you download and try this out. please tell me if element up does affect elemental shelling damage. 

just fyi: ELEMENT DOES WORK NOW BECAUSE STATUS/STUN/EXHAUST WORKS, just like CB's phials

Shelling types: Normal prioritzes burst damage. Long=Charged shells and Wide=normal shells. All shell types have different playstyles
So if you want to deal good elemental damage make sure you are using the right moves depending on shell type.

Normal: Highest exhaust on burst/deals decent elemental damage on burst and low on other shell moves. (bursting playstyle)
Long:      Highest stun damage on charged shells. Good elemental damage on charged shells.                           (mixed playstyle)
Wide:     Decent  stun/exhaust damage on normal shells and decent elemental damage on normal shells.     (poking playstyle)


CHANGES:

This is what I scaled the shells with via phials:
Normal shell : Sword phial
Charged shell: normal Phial
Burst   shell: AED phial
Wyvernfire   : SAED phial

Charge blade phial base numbers:

IMPACT PHIAL:
NORM: 30(stun)/5(exhaust)
AED : 35/7
SAED: 40/10
SWORD:15/3

ELEMENT PHIAL:
norm: 2(element)/1(status)
AED : 5/1
SAED: 9/1
SWORD:1.5/1

Charge blade phials to shelling scaling:

scale rate:
  (sword/norm/aed/saed) of phial value
Low:   50%/25%/10%/5%   of phial value
Mid:   75%/50%/25%/10%  of phial value
High:  100%/75%/50%/25% of phial value

shell stun/exh scaling:

Norm: low  stun/low exh(norm shell)/low stun/low exh(chg shell)/low stun/high exh(burst)
Long: low  stun/low  exh(norm shell/high stun/low exh(chg shell)/low stun/low exh(burst)
Wide: mid  stun/mid  exh(norm shell)/low stun/low exh(chg shell)/low stun/low exh(burst)
wyvernfire: all scales with 25% of saed

shell element scaling:

norm:low  elem/status(norm shell)/low elem/status(chg shell)/high elem/status(burst)
long:low  elem/status(norm shell)/high elem/status(chg shell)/low  elem/status(burst)
wide:high elem/status(norm shell)/low elem/status(chg shell)/low  elem/status(burst)
wyvernfire: all scales for 25% of saed

Other changes:
Shells:
-Overall shelling multiplier is increased from .67 to .7
-Normal shell(shell type) shells reduced from 5 to 4, burst damage increased from 1.2 to 1.25 (same damage, adjusted to make up for the reduced shell)
-Shelling count before wyrm stake is increased from 2 to 3 (to allow for more normal shell(attack) spamming
-wide shells increased from 2 to 3,full burst damage reduced from .9 to .55(same damage,adjusted because of extra shell)
-yellow gauge debuff from -15% to -10%

Shell sharpness consume:
-all normal shelling consume from 2 sharpness to 1
-full burst (per shell consuming) from 2 sharpness to 1
-wyvernfire from 10 sharpness to 5
-wyrmstake from 3 to 2
***All reduced to allow more use of shelling

WYRMSTAKE CHANGES:
Wyrmstake is low key broken but people don't use it much.
Uncharged shelling damage reduced from 1 to .5
charged shelling damage reduced from 3 to 1.5
full burst damage reduced from 1.65 to 1
wyvernfire damage reduced from 3 to 2

Why the nerfs? because it's too strong and with the shelling buffs it would be too broken(tried it out)
However I will increase the duration of it from 180/110/60 to 300/240/180
Duration goes like this -> Strong pods/medium pods/weak pods
***wyrmstake explosion doesn't have any element because it's hard to balance out as it doesn't depend on any shelling type.