Ok, I think I have a solution that might work for you. I think you should be able to mount Team Associated B4.1 steering blocks and axles in the Helion caster blocks with a little bit of massaging and the right spacers. The parts I would think you would need are as follows (links just included for ease of use, you can find these parts at Tower or other sites as well):
https://www.amainhobbies.com/team-as...-asc9581/p2443
https://www.amainhobbies.com/team-as...sc9612/p182840
https://www.amainhobbies.com/team-as...-asc4187/p2786
https://www.amainhobbies.com/team-as...-asc3977/p7978 (or equivalent, you will need 4 total bearings and these are a different size than whats on your Criterion)
Instructions for how this would piece together can be found in the B4.1 instruction manual (
https://www.teamassociated.com/pdf/c...-preflight.pdf) starting on page 4. If you need more clarification, just let me know and I can try to explain it better.