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.