I'm in the W&SS/Beckerhead challenge of which you speak, too, and I don't think anyone involved would think less of you for doing some research. That's not cheating, it's just smart
This challenge is set up specifically for slicing/cutting knives, they were very clear about that. Those folks also do chopping contests and other fun stuff, but they totally understand the difference. They're not going to baton a 5" slicer through a cinder-block.
Thin is in for this challenge. .098" stock will make it easy to get a keen grind that will cut well. .204" is WAY too thick for a knife that size that's meant to slice, unless maybe if you use a small-diameter wheel to develop a deep hollow grind... which can give a very thin
edge, but will still have a thick spine that will bind up before it gets halfway through a tomato or thick rope.
Go with the thin stuff.
Elmax is
truly excellent steel. Grind it as keen as you can, have it HT'ed by someone who really knows what they're doing, and you will not be disappointed :thumbup:
Pay extra attention to the comfort of your handle, too. Those guys have a lot of experience with hard-working knives, and I don't think they'll be impressed by a blocky handle. Good luck!