TW90 small wheels and contact wheels questions...

[gdpolk]

I see on Travis's site that he uses Bader type wheels for the small wheels fork and contact wheels. This leaves me with a few questions:

1. Where is the best place to source small wheels for this setup? When I look on Bader's website I see three options for shaft type; what is the correct one?
   
2. On the larger contact wheels, do these attach with an arbor that slips into the tool bars so that you can easily change between contact wheel sizes like on a Dozier grinder or are the large wheels screwed into the tooling arms making them a more permanent mount which is more typical of the KMG type grinders? Where are the best places to source contact wheels for a TW90? If using wheels off of a KMG type setup is there an adapter available to make these work?