I don't think I can get any new ones in time. I'm going to sand and polish the wheels. What else should I do?
I think I would hit the Scout store and pick up about a dozen wheels. This is a really crude version, but drill a hole in a block of wood with a very smooth side on it. Find a very straight axle and use it to test spin all of the wheels. It is nice if you the block of wood is tall enough to draw some parallel lines on the side. They should be about a1/16" apart. Use this to help identify radial runout. It would be best if you put a drop of lubricant on the axle before spinning. Look for both lateral and radial runout of the wheels. Turn the block so the wheel both rides on the inner hub and then the outer hub. Pick out the best wheels and use them. Do not sand them! Do a bore prep for your lubrication choice and run the wheels that way. There are a LOT of wheels that run slower after trying to sand them. There are a number of reasons why this doesn't work for most people.
Sorting thru 10-12 wheels has normally yielded 3-4 wheels that are decent. Yes, this does make a difference.