I went with a relatively low power bow and used an axle for the nut for simplicity so this is more medieval style as the draw weight is too low for a proper battle crossbow.
It draws about 170lb at 5 1/2 inches.
The tiller is 34 inches long and is made of European Ash and the nut made of buffalo horn (since replaced with antler)
The steel bow/prod came from Todsstuff and is very similar to medieval bows and tapers in width gently to the tips. Also has hand forged rolled ends.
Looking back it's a bit bulky in the tiller, and could do with being a bit narrower around the bow socket, but I've had good results shooting it in terms of range and accuracy.