Well it really depends if you're using a gen dial or not. If you have a gen meters first 5513 dial, it's crazy talk to cut the feet and slap it on an ETA. Completely destroying its value. You gotta preserve the feet and use a gen cal 15xx. You could always sell the dial and movement for close to what you paid.
If it's a rep dial, yes, no point using a gen movement (eg TC).
I suppose you could grab it with a pair of pliers ghetto style. I use a gen Bergeon 6767 but I think there are cheaper knock offs that will accept that tip as well. Just get one of those instead. Its fraught with peril if you just get the tip.
Like my dad always said, "use the right tool for the job. Don't shortcut."
The ST bezel is matte raw stainless.. it needs to be polished before its acceptable. but yes, the ST bezel assembly will fit only any gen spec case/crystal. As for the insert, it's a tight fit on the bezel but most inserts should fit. But I ahve heard that somehave needed to slightly shave the insert to fit..