There are several factors to consider IMO:
1- Technical limitations of the deck -i.e., can it operate with a higher output tape?
2- Long-term stability and availability of 211
3- Aesthetic preference for a particular tape and/or a particular tape’s sound on a particular machine
1- No idea myself, as I’m not familiar with that deck
2- Not sure, but would guess it’s likely similar to 202 and would perform fine, perhaps with some degree of fragility. The link ofajen sent above:
3M Audio Open Reel Tapes … seems to indicates that 211 is the same as 176, which appears to be a later incarnation of something resembling the tapes in the 111/202/206 family.
3- This comes down to personal taste - for instance, I prefer Scotch 202 for mixdown on decks like the 1960s Ampex pro machines, but think Scotch 206 sounds better on something like the Teac 3340. I also used 206 or even Quantegy 406/456 on multi-tracks, as 202 does not hold up as well to repeated overdubs etc. I like Ampex 631 tape on the little Ampex suitcase machines … so IMO there is something to be said for using a tape formula that the deck may have been designed around. Main takeaway here is: there is no replacement for personal experimentation if you are looking for a particular sound or picky about that sort of thing.
If it were me? I would grab an NOS reel of 211 from eBay without hesitation, and try it out. I would also personally compare that to the sound of a more “modern” tape like Scotch 207 or Quantegy 407 to see which I like better. I would not buy new tapes, but I think there is an RMGI (or whatever it’s called today) formula that is equivalent to 207/407 but someone else with more familiarity can chime in there. The question seems to be whether or not your particular deck can calibrate up to the “modern” tapes. If you are going to get into this sort of stuff today, there is no longer really an organized support system for these things so you'll need to find a local tech (and/or be good with electronics yourself) and find your way using your own experience. This particular forum is the best resource IMO, but activity here has dwindled within the past few years, and places like Tapeheads might be better suited for info these kinds of machines (I don't participate there myself, as it's geared more toward the hifi crowd as opposed to the creative recordist).