Lewm,
That is a good point about belt contact with the platter. My SME 10 has about one inch of exposed/free belt before and after the motor pulley leaving the vast majority of the belt in contact with the platter. This is in great contrast to some other designs which have a motor on a remote platform 9" or more away from the record platter. Tables like the Walker, the Raven and the Micro Seiki all have a lot of exposed/free belt which is why some owners have switched to thread, I think.
I have not tried the Timeline on my SME or read of anyone else doing so, but the SME tables have a reputation for having pretty constant speed stability and accuracy.
I started this thread a while ago, and I appreciate all of the contributions to it. I have learned a lot. Thank you to all those who have participated.