Right. I like the idea, your on. 
You think, though, that lever height has to play into the ratio? The longer the lever, the greater it's height will need to be?
Okay Parnell. Today i bought a 4/4, quartersawn, white oak board and cut it to 66" long. This is what i did with it so far. ($25 for the board, $1 for 3 table saw rips at the local hardware store, and i get 3 kickass bows...gotta be optimistic)
I got a little heavy into the puffing and didn't do much passing at all, so i made a couple oopsies...on the other hand, i made a cool (creative) mistake that led into the bows having the shape they do.
I decided on a 1:2:4 ratio for the fades, transitions, and tips. What i mean is, it is 1.25" from the end of the handle to the full width of limb (very fast change); THEN it is 2.5" where the bending limb changes into the lever; FINALLY i will taper the last 5" (toward the end of carving this thing) to reduce the weight at the tip. This ratio just evolved naturally (puff puff) and i'm gonna go with it.
LEVERS
These will be almost full thickness and as narrow as i can make them. I plan to make them all the same thickness and width, so i can gauge the effect of their length. I'm thinking maybe 3/4" thick the whole way (up to the last 5"), very rounded, maybe 1/2" wide.
BENDING LIMBS
These are 18", 15.5" and 13" respectively, including the fades but not including the transition to the levers. They are 1 15/16 wide. I'm going this wide to prevent set...i hope i can, anyway, that's part of what this is all about. I'm gonna make all these bows pull 50#, trying to keep everything the same except the ratio of bending limb:lever. Be interesting to see how thick each one winds up...any guesses?
HANDLE
4" long plus 1.25" fades each way. Hump style. It will be maximum 1" thick, i'd say.
and hey! I don't mean to highjack your thread...just wanted to make sure you knew about this one. Should take awhile to make the 3 of them, but it'll be a cool experiment.
Here is one of them laid out and cut.
The last pic shows how the board was skip-planed. I'll have to take about 1/16 off the back of each one. They were almost 9/8 thick to begin with.
