i like the clean look of slotting the bag and having the bulk of the strap inside and there is no change of the buckle beating up on anything. i also leave the strap a bit long to accommodate different applications. many of my bags end up mounted at the bottom of the down tubes. fork bags are generally mounted with the strap over the triple tree so there is no need for a vertical strap.
BTW.. i use 10 oz leather for my bag bodies plus the 2-3oz lining.
there are many ways of doing things and it is always nice to see something fresh and the reasons why we do it that way. i hadn't though about setting a strap by hammer it down but, that sounds like something i will try
you need a camera Hidemechanic!!