Stoptail plugs are 5/8 inch aluminum sewing buttons. I still need an attachment for them. Saw that over on another forum, and asked how it was done.
Roller bridge is not needed on the 33x series. See the break angle over the bridge? Its rather shallow. Works fine, returns to zero quite well.
On an SG though, they suggest the B5 Bixby. DONT. Just DONT. The B7 (not the imports) is the way to go. It fits, AND since its hinged, you can shim the front to achieve the break angle on the bridge as you desire. And it sort of looks... sort of... similar to the Meistro they had (and works better too).
B7 on a Les Paul can be similarly shimmed.
B5's work on Tele's - others too - but Teles are the main reason for their existance.