SME Tonarms, SOTA Vacuum Turntables, and 10" Records

@jazzguy43
If you need a blank disc, check out Ebay for a Donna Summer 12" single side on the Casablanca label. You can get one for under ten bucks. I use this for adjusting anti-skate.

I have a vacuum clamp table (Basis Debut).  It cannot seal a 10" record.  This is not the end of the world.  Just turn off the vacuum and use the center sealing puck as a weight.  Yes, you won't get the tight coupling of the record to the platter, but, there is no point to having a blank record seal tight to the platter if there is no way to tightly seal the 10" record to the blank anyway.  

Having owned a SOTA vacuum turntable I get what the op is saying.
It won't suffice to just turn the vacuum off ... which on some (most?) SOTA models can't be done anyway as the platter motor and vacuum are controlled by the same switch.
Without a (12") lp pulling the rubber lip down flat when the vacuum is engaged, the rubber lip is angled upwards and fouls the thick part of the SME arm.
One way to get around this is to use a spacer under the cartridge
so that the whole arm sits a little higher for a given vta. This should provide enough clearance for something like the SME.
Used with a clamp the vta would remain the same for both 10" and 12" records assuming same thickness.
I have seen some spacers made of ebony and of graphite for sale. Also  the Music Man cartridge isolation device would work in this instance.

You could also use a rim weight like some other turntables use (VPI) - it would hold the lip down so it couldn't hit the platter.

Frankly, I think your solution is just fine - I own a Sota Cosmos but if I have to play 10" I just do it in y other system.