Yes,Stos broahead have a oval shape ferrule.
This is what I do for a perfect fit brodhead/adaptater or insert.
I use epoxy glue, put some glue on the insert tip and inside the broadhead, put the insert (stand up) on a hard wood piece , put the broadhead on the insert and with a hammer hit firmly the broadhead point.
This is smash a little bit the broadhead point but you can correct this very easely with a file ,but in my case this is not a problem because on all stos broadheads,I cut the point (i take off 3/16) to do a nice tanto point.