David ,when i first started doing leather work,i ,like you wanted the Smothe rounded
ends on belts & wrist bands.
the strap ends punches were expensive and they still are.
go to the Hardware Store and Buy yourself one each of all size of flat Washers.
then you have a Template of what you will need to cut the strap ends.
then use an Exacto Knife or a Round Knife to cut with.