Yes. The 5" traction wheel is a VRC product. Just have documentation in case the inspector or ref are new enough to not know they are a retired product for VRC.
You are forgetting about the 5" traction wheels that were a VRC product for years. Additionally, you could start with a 4" wheel and build it our using VRC legal rubber bands. There are other ways you could build it out using Vex legal parts to come up with a 5" fly wheel but, as I said building it our would not work as well as using legal 5" wheels (not flex wheels). 5" wheels product number is 276-1498
While I am only a middle schooler I do ref for in class scrims.
This was not my team but they were from my school and they were playing defense and the robot they were defending chain snapped. Then they got a DQ for assistive defense. but it was a building issue.
At the last spin up tournament I went to, the ref’s and scorekeepers were not well educated. I think it was the school’s second year doing tournaments, so its understandable.
A ref misread the rule that says you can’t expand in the low goal, and thought it meant that you couldn’t shoot in the low goal. There were a bunch of cata teams that shoot partially from partially within the low goal. It didn’t affect matches much, but they DQ’d anyone that shot within the low goal.