"Although Unity tends to fuck up its physics"
Gee, no kidding. The game runs at 2 times speed just so that the ball doesn't fly off when it passes over the invisible edge between two segments of track. Oh, and it does that, just 0.4x less. Then I exported the level into Blender, simplified it, and imported it back into Unity. It's a single mesh collider, so now the ball jumps up 0.2x less every time you strike!