For now at least, I give up the idea of working on a wood prod. I'll build a composite one in the future though.
So, I wanna build a spring steel prod (there's a metal shop nearby who sells 5160 springsteel flatbars...lucky me )
Anyway, I want to use the same tiller I was to use with my wood prod... it's quite massive but I'm a big guy as well. The draw length would be 12,5 inches (I'd say I'd brace the prod at 3-4 inches and the rest would be the power stroke. The prod should be 2" at the centre and tapered toward the knocks but I'm not quite sure how I should do it (I would work it carefuly with an angle-grinder and have someone at the shop to heat-treat it. In the final, I'd like the bow to be around 250-300 pounds of draw weight. I guess the prod knock to knock should be around 34-35 inches to be safe ?
Any ideas about the specs ? I did some research but I'm still pretty much in the dark right now...