X2- 2 parts liquid to 1 part powder. I measure using plastic spoons and mix in a clean yogurt cup. If there's any glue left over, let it cure in the cup then turn it over and rap it against the table to loosen the old glue. The cup can be used over.
If you want to use TB3, just make sure that the mating surfaces are as perfect as you can get them so there's no gaps. Brush glue onto all mating surfaces and clamp carefully without using too much pressure. Glue squeeze out is ok, but don't starve the joint. I have 2 bamboo backed bows glued up with TB3 and they're both solid.
Dave.