It's kind of borderline, just a weird part of the game mechanics. Changing it would prevent more levels than you'd think.
EDIT: I think it would be better just to leave the little glitches in. The ones that really need fixing are things like the nuke glitch.
EDIT2: The columb set has different pieces than I thought it did. It will take more than 8. It turns out that it's like you said, two curved pieces with lots of black pieces in the center. Maybe you could get the level data from a genesis rom and see how they do it?
EDIT3: Those rings in Ahribar's level are copies of the ones from the genesis version. It looks like they were filled in with black pieces. So you either stuff a bunch of black pieces inside, or make it a special graphics level (or maybe just change the scenery).