Are there any parts you think are particularly important to acquire as spares?
I think for both the TT-81 and TT-101, every part (including chips) is available (just Google the part No.).
There is just one special power chip which is scarce and Lewm has snaffled up a bag-load of these, one of which he has kindly sent to Thuchan who needs it to complete his rebuild of a TT-101 I found him.
Will be interesting to see if he ever gets it going...👅