Stacking mats on Technics SP-10R

Whatever you end up leave a silly millimeter for an Origin Live mat in top.

Wouldn't it be easier to make a jig and drill them all to be centered? 

Sorry, I don’t get why you need to stack mats in order to correct for eccentric 78s. And most of us wouldn’t know what mat sounds best with old 78s, which I assume could be shellac. For vinyl, I definitely would not recommend the original SP10 mat(s).

Your plan makes perfect sense.  Any generic rubber mats will do the job.

Bill

lewm, He has 78s with holes off-center. Stacking mats raises the record to the top of the spindle allowing him to position the record to be centered on the platter. He could drill a whole stack of them all at once and have them be centered, but for some reason prefers to mess around fussing with them one by one by hand.

I'm with fuzztone on the OL mat.

Thanks, MC. Now I get it. He needs a nakamichi TT.

"  An engineer friend who does a similar thing said he just collected old Technics SP-10/15 mats. "

doesnt the OP's answer his own question ?

stacking mats will work of course but it seems you might want to consider a rigid solution for the majority of the 'lift' ( metal, pom, whatever you think is right ) and then a single mat.

Stacking mats will jack VTA so far out of kilter I'm amazed anyone who cares at all about sound quality would even consider it. Especially since what it means is trying to center the record by hand. 

So imagine, you got a record on a stack of mats 1/4" high, which means VTA off by a whopping 1/4", playing a record wobbling around - and this is at 78rpm! Crazy!

reading comprehension not a strength, see OP statement about willingness and capability to adjust ….VTA

With the problems of 78 rpm and the cost of the SP10R it was better to buy a used Nakamichi TX1000 and no more problems.
There is a serious risk that the remedy to improve reading of eccentric grooves by adding mats to mats is worse than evil.