If I'm reading your post correctly you've gone about things bass-ackwards

You shouldn't glue the gas cylinder on until you've fitted the gas cylinder lock.

The gas cylinder lock gets screwed on until it stops against the barrel shoulder and then is backed off until it aligns with the gas cylinder. The gas cylinder lock screw is then inserted and tightened to draw the gas cylinder up to the lock.

That way there is no gap between the gas cylinder and gas cylinder lock to deal with.

You do want a gap between the gas cylinder and front handguard to allow for barrel expansion.

Thread timing on individual barrels and gas cylinder locks is what it is; there was none specified. As far as the Army was concerned, even if a lock had to be unwound from 4 o'clock it was still good-to-go.

On match conditioned rifles a gas cylinder lock that stops finger tight on the shoulder at around 5 o'clock and is tightened with a wrench to 6 is desireable. About the only way to get one is to have a bucket of locks to pick from.

Maury