Thanks for the comments.
I started this knife with .135 thick S30V barstock, it is not ground to a zero edge, but it is ground thin. I can flex the the blade on my workbench. After discussing this project with my customer he as the same likes of a fillet knife as I do, which is a little stiffer than those $10 fillet knives, when I was doing alot of fishing I used to fillet with a Russell boning knife, so anyway it isn't wispy thin, but its what I'd consider a good thickness