I've done about 4 Z-spliced yew longbows (full compass, bend in the handle) now without any power tools. A good quality Japanese pull saw does the trick for me. Just draw the Z splice out on both limbs, clamp it into a vice and away you go. Shouldn't have to do too much fiddling after it's done, but some light rasping on high spots can help.
The two ends are then boiled for about 1 hour, and clamped together hard in the vice for a day. Pull them apart, glue them up, reclamp and you're done.
If you happen to get it badly wrong and the cuts just aren't clean enough, you can make shims for the join out of the excess wood. Small thin pieces are glued on both faces and with the two limbs pushed together, you lightly tap the shims into place.
The only splice I've had fail on me so far using the above method was a bend-in-the-handle 140lb yew bow, and it only failed because the splice wasn't long enough.