You can spend however much you wish to try gaining incremental changes in the performance of the main bearing. The 1 micron Zirconium marbles seems to make sense and will certainly sound better than the 30 weight Quaker State motor oil. You have to consider however the other limtiations of the table before you can expect any real world gains from tweaking the spindle oil. The TD 126, if for no other reason than its age, has a rather unsophisticated main bearing pulley. You know the quality of the belt better than I do. The motor is still putting energy into the platter assembly. The plinth is very light and not well isolated from external forces. The arm is less revealing than a low end Rega by today's standards. Etc., etc., etc. So how much should you put into the main bearing tweak and how much should you expect to gain? This is the question any tweaker of vintage components has to answer before giving anyone their cash. If it were my table, I'd spend a few dollars on some fairly inexpensive middle weight oil with either Teflon or a silicone based synthetic. Put the rest of your money into getting a more sophisticated isolation support for the table. (A wall mounted bracket should work well for the Thorens.) The Thorens tables are notorious for responding to footfalls and low frequency feedback. Fix that and you will hear more music than any bearing oil can allow through the muck and mire.