I run Total seagapless rings in my engines also, but you still have to file them to fit, they still have gaps, they have to. The difference is a two peice ring that has stagered gaps to seal the cylinder. I think you asking about gaples v/s standard rings. As for the file fit there are two types of standrd rings, file fit and "pregapped". The "pregapped" you just install, while the file fit rings are slightly oversized so you can set your end gap to what you need it to be. The "pregaped" rings are designed to fall within stock manufacturers specs. But yes, gapless rings work very well.
I've run both zero gap rings, and file fit rings in my methanol engines.The zero gap rings will show an excellent leakdown, but don't seem to run any better than conventional file fit rings with my experience.