RE: Arrow insert and broadhead question
i can' t answer the insert question but i' ll take a stab at the other two.
I shoot the Rocket Sidewinders and they come w/ washers and rubber band as well. Yes i place a washer between the broadhead and the arrow. The impact of the mechanicals opening up have actually left some indentations on my inserts (with washer in between). They open up w/ some pretty good force.
Typically my rubber band slides back the arrow but occasionally they have broken. Rocket gives you a ton of them so that' s never been much of a concern as far as them breaking or re-using them.