3:1 is fine.
If you make the opening of the female part 1mm or so narrower than the width of the male part you don't even need to clamp

If you use any collagen glue then just wait a few minutes for the glue to gel and then clamp away if you need to . The parts will not move.
Another trick on things like this is to use parcel tape. A fe pieces put on under tension back and belly would hold it all in place to allow light clamping.
Another option is to clamp the limb section to a scrap board with clingfilm inbetween. Do the glue-up, fit the parts . Clamp other piece to board and then apply clamps.