Marty, If you want a tri-lam I'd use the 1/4" ipe strip, 1/8" action boo, and a bamboo backing thinned to an 1/8". On these slender bows you must make sure you have a constant taper. If the limbs go to one side or the other its usually a lack of taper causing it..
Make sure your bamboo is even thickness on both sides since while these skinny bows require a little more precision when it comes to symmetry. Cut the belly out first and get it floor tillered to go into your form easily, and if a tri-lam like to glue the core up first, and let it dry..Then I glue on the backing with the curve amplified a bit more perhaps pushing the tips just past the handle.
Same applies to a backed bow, but you will have a thicker belly piece 3/8" and 1/8" bamboo.
A powerstrip will thicken the handle and can look cool, but it won't make the bow any faster..I do use them occasionally to have the grip rounded out some. Just make sure the bamboo easily bends around it and conforms..sometimes a put a little clamp there with a tiny strip of wood right at the transition points.
Rich-back to the sawdust pit