I dont own those Tesla tech. Beyers but Crack works well with all my hi impedance phones, including my 120 ohm AKG's. I have Beyer 880's and 990's, both 250 ohm and they are fantastic. I see no reason why it wont be a great match with the T1's or T90's. There is/was atleast one member here with T1's. Try a search in this forum.
I do have Tesla T1 hooked on a Crack for at least 18 months and I have absolutely no regrets. I used to have a pair of Grado SR225 that we now use for the girlfriend when she wants to watch TV on her own.
I use a 6AS7G "built in Germany" and a 5963. I have like 20 other tubes to try and I think I'll just wait for the actual set up to blow; it is just so good and enjoyable, I don't want to interrupt a good thing!
I am currently using the T70 with my stock Crack, still waiting on my speedball but initial impressions are good, some of the treble can be a bit harsh on some tracks but that seems to be expected. Good amount of bass as well.