Hi, Thunderwave!
I would think that Mozart would probably be subject to the temperament of any of the keyboard instruments that he used at the time, be them the forte piano, harpsichord, clavichord, virginal, spinet or organ, etc. if he was not able to tune them himself.
Most of the players at that time, tuned their own instruments that they would take with them. If they were not able to take their own instruments with them, or tune the instruments on which they would play, then they would be subject to the tunings and temperaments of the instruments that they had available that were extant in the location that they were playing.
Being a professional pianist and piano tuner technician, it's frequently that same way for me.
Unfortunately, there wasn't one type of temperament in use in Europe or other parts of the world at that time. So, we can only guess at what the prevailing temperament might have been the preferred one used by Mozart. It could be that he actually preferred more than one kind of temperament. Certain temperaments lend themselves to be better used for a solo instrument and also when used with a group of musicians playing together.
The way to tune according to the 1/6 ditonic comma temperament is described on the following site.
http://www.terryblackburn.us/music/t...ng_Handout.pdf
Pianos can be tuned in a number of different ways. According to the historical records of temperaments and the ways to tune by them, yes, you could have your piano tuned in the way that you mentioned. I believe that there are even electronic devices that will facilitate tuning in a number of different, historical temperaments.
If you'd like to discuss more about piano, I would welcome the opportunity.
Thanks!