What 3M types are not subject to SSS Beck?
I've never had a bad reel of 3M 206/207 or 986. 226 is a different story. It was meant to be a bias compatible competitor with Ampex 456 and it was one of my favorites before SSS reared its ugly head. Now 226 is the worst, so avoid that.
206 was the older formulation, but when you consider 206 is what Tom Scholz used to lay down most of the original tracks for the Boston debut album, you stop worrying too much about +/- 3dB this way or that way. And he started with 12 tracks on a 1-inch Scully... home recording 1976 style.
I use 1/2-inch and 1/4-inch tape. I haven't paid more than $45.00 for a reel of any kind of 1/2-inch tape since "The Tape Crisis" when Quantegy suddenly closed its doors. And much less for 1/4-inch tape. I have a good stash though. It's easy for me to take my time. Searching with common misspellings and typos people make helps me find NOS that no one even sees. The downside is we're dealing with mostly amateur sellers, so helps to ask questions.
This would be more difficult in a busy commercial studio. I don't have to worry about that either.
I am surprised at the number of people who purchase well-known SSS tape however. I'm sure many people do it knowingly with the misconception that they can bake tape for future use. Not a misconception to their mind though... they think they know an insider trick or just want the metal reels if it goes for really low. It seldom goes low enough for that IMO.
ATR and RMGI are ok, but insane high prices people have become accustomed to. It's like ... oops I didn't want a second car... but just a reel of tape.