[Closed] Helmet fitting question

Been trying to find a light full face that fits. Both sizes met parachute fitted terribly.

The Large Bell Super 2R fits well when the dial is almost completely tightened. It stays in place when I wobble it, is snug, without being tight and uncomfortable.
But is it a bad thing that when the dial is not tightened, the helmet is quite loose on my head, especially side to side (not helped by the very round, wide shape of the upper piece). But I just can't see the medium fitting my 61cm head.
i.e. is it ok to rely on the retention system to ensure good fit, or should it fit fairly well without that??