These are the steps I took to get these results.
0. I upscaled the vanilla texture to 2K
1. I color matched skin tones of the vanilla image to the CBBE image.
2. Overlaid both images and decreased translucency of the top most image by 20% until I reached 100%
3. Blended the CBBE neck over the vanilla image using an obscure program no one has ever heard of "Adobe Photoshop"
4. Saved them back to DDS with DTX5 algorithmic compression <-- See big scary words. You can't do this!
This process is extremely dangerous and requires that you have an industrial 3 phase 480v power feed coming into your laboratory of whatever science facility you work at. Don't try this at home. I'm a trained professional.
Lecturing at Penn State in the Astrophysics Depart and work history
I taught and lectured individuals who were hired by their uncle for the summer to lay carpet in the astrophysics dept at Penn State. I also worked as a resident Brazilian wax technician's apprentice for under privileged bikini / panty / lingerie models for the non-profit group Beauticians Without Borders.
Dr. Steven Hawking and I.
I conferred with a man who told me his wife's brother was a gardener for Dr. Steven Hawking until one morning he lead the police and later arrested at the iron gates of Dr. Hawking's estate for driving while intoxicated. His car had to be towed from the driveway at the expense of Dr. Hawking and he was no longer allowed on the premises.