RE: .28 in a funfactor? oh dear....
They don't fit the CEN cups you will have to make a new adapter to use the maxx cups. The maxx cups are held on like the ff047 center dogbone cups. I thought about turning down a gx12 to work but I don't think it will be long enough to properly secure the maxx cup. So I am just going to make the "adapter" out of a piece of stock about the same diameter.
In order for me to do your mod I will have to buy some CEN cvd's and then the rest of the maxx stuff. This way I might be able to cut down on some of the expense. I don't want to cut my only set of cvd's incase I decide to go back to the 2.2 wheels.
This idea might work for your mod. It will definetly save on the expense of cutting the CEN cvd's.
rolland