Piston ring end gap

Mine measured out .018"-.021" which was within the piston manufacturers spec for a normally aspirated gas engine. Mine weren't file fit but since they were within spec I put it together; doesn't use oil and no oil blowing out of the breather at full throttle so its all good. The important thing is that the gaps are not too small which will cause rings to butt resulting in catastrophic damage. There are usually different specs depending on how the engine will be run; for example more ring gap for nitrous, turbo, and super charged engines.

The oil rings had real big gaps which I was told was ok.

Your engine combo sounds real good.