I'm not a Thiel guru, but it sounds like tube amps are not a good match to the Thiels due to difficult load.
You might be better off going SS on the amp and tubes on the pre-amp, if that's the sound you like. The SS amp should double power to 4 and 2 ohms as discussed above due to the load.
I'm sure others may have some specific suggestions regarding what works good with Thiels. If it were me, I'd consider some of the better Musical Fidelity amps of perhaps something Class D, like Bel Canto or Rowland maybe.
You might be better off going SS on the amp and tubes on the pre-amp, if that's the sound you like. The SS amp should double power to 4 and 2 ohms as discussed above due to the load.
I'm sure others may have some specific suggestions regarding what works good with Thiels. If it were me, I'd consider some of the better Musical Fidelity amps of perhaps something Class D, like Bel Canto or Rowland maybe.