Is it OK to hit the gimbal with a few shots of grease while idling on muffs?
Personally, I think the proper way is to have the drive off when you grease the bearing. pump new grease in till you see it coming out of the bearing, turn the bearing and repeat, turn and repeat.
Then clean up all the old grease before it gets spread all through the bellows and all over everything inside the bellows.
Then check your alignment again, grease the splines on the ujoint shaft and install the drive.
Everything is clean and neat.