Not sure if this has come up before but…
The nothing but net balls looks suspiciously like the small clean sweep balls and the balls in the classroom competition. (they are all 4 in in diameter)
Do you think I could use old clean sweep balls/ classroom competition balls in place of the nothing but net ones until my club gets a field if I want to run some tests with different wheel types?
Yes, you could. I was talking with the VEX staff member who managed the new game field at worlds and he said they where almost identical.
The field specs are up now, NBN balls weigh 0.11lbs, Clean Sweep balls weighed 0.125lbs. So looks like they’d be a good fit!
I can’t see a problem with using the clean sweep balls for testing. It will at least let you check your designs. Hopefully if there is any difference in the balls it should require only minor tweaking. The only problem that could occur is if for some reason they use a different ball material / density which is unlikely.