If the wheel is truly out-of-round, I would think all they would have to do is dismount the tire and put it on a lathe. It shouldn't be that much of a time consuming repair.
Just explain to the guy you have to have it back by Thursday, and maybe slip him a tip for his consideration.
My concern is the long term effect the 10mm spacers may have on your wheel bearings, tire, and brake pad wear.