There are different ways to stabilize skin that have different results. One is tanning ( like shoe leather). Another leaves you with parchment, and the third results in something American Indians wear (raw-hide or buckskin). Given that the client is an artist, he probably has a picture in his mind of what he expects it to look like, so you need to discuss the options even before you talk to taxidermist or go on line for instructions. On the other hand, you may find that one method or another is easier to do – and less stinky.