I am doing this right now to a set of motron snowflakes. The front wheel takes a 6201 bearing just fine. the rear wheel takes a 6202 bearing. The ID on the 6202 is just a little big for the axle, so you have to find a little spacer or a bigger axle. I found a little pop in spacer for the 6202 bearing in a front kenitic wheel. This may help. The wheels have a nice cup to seat the bearing in. If you need sealed bearings go to a place called Motion industries. They are rad.
Remember this is on a italian motron snowflake. Hope this helps a little. we have mixed and match tomos and minarelli rims for some bikes.