Well, for sure you don't want to glue the deck sheer strips to the internal stem. That would create a problem in separating the hull and deck! The internal stem should be a replacement for part of the wood in the bow end form. You can think of it as a part of the end form that is detachable and that stays in the finished boat. I think it would be logical to extend this detachable piece up to the sheer line but not beyond it. Going past the sheer would make separating the hull from the strongback difficult. Your deck sheer strips should have some support at the end and this should be the end form, which will have a fair taper on the end to staple the strip to.

Mike Scarborough
Friendship Kayak