ipe/ hickory question

[doulosparachristos]

so i have a longer pyramid flatbow planned out ( 71'' & just under 2'' wide nearest the handle) using some leftover wood. the question is; what thickness should the backing (hick) vrs the belly (ipe) be to get around 60# @ 28? im asking this question because both belly and backing are already cut at 3/8ths and my cutting tools are not the greatest, so i want to make sure i get it as close as possible befor i start. thanks for any advice guys, i need it all.

Roy

[bubby]

1/8" on the backing, ya can rip it a hair heavy so ya can sand it out, 2" sound's awfull wide for epe,I built a 70" ntn flatbow boo backed epe 1 1/8" wide at the fades, and it was 72# @ 29", 2" wide might get real thin, jmho, Bub

[M-P]

Howdy,   All my ipe bows are made pretty narrow,  3/4 - 1 1/4 " wide and still  less than 3/8 inch thick in the working limbs.  I don't think the backing thickness is critical, but is normally less than 1/2 the limb thickness.   If you glued up what you have now, it would be a really heavy draw weight bow. 
Ron