So that looks like an amazing fit! Mine do not roll by themselves. That is what you have been worried about this whole time? So these bearings will seat themselves a bit after some use. I'm more worried that you will not be able to get it tight enough later. The surface of these pipes is very inconsistent, they are not expensive polished rails. They will be a bit rough at first but smooth out very quickly. Once you get it up and running a few laps it will be much smoother.
Finish it up and lets see some powered movement!