I dont know much about knives yet, but i would say .210 for thickness. I have a Fehrman in a size similiar and i would a slightly thinner blade in that size would be super. Still take a beating but be lighter and faster. I dont think .266 is needed for that length. but honestly i could be completely wrong.
I can see arguments for both sides. .266 would be a bit of a brute and the grinds not going all the way to the top means a less steep angle - the edge getting thicker with each resharpening. But the extra weight would help with chopping and batoning.
A lighter/thinner blade will slice better and the edge will not "thicken" as quickly with resharpening. Lighter is easier to carry. But we gotta remember that 0.210" is no slouch in steel thickness! It is thick enough for sure.
Dan, just dropped in and saw this. I see .210 being bandied about, but being number/math retarded, what does that translate to in fractions of an inch? For a knife this size, I would lean towards 3/16ths, myself, and A2 would be fine with me. Do you have a projected cost on this model?