You may want to consider an overflow feature that allows an outlet against overfilling. Also, you may want to put bleed holes near remote locations that are starved for grease. We had a worm gear that had trouble receiving an initial charge of grease until a small bleed was located near the critical location.
I can't help you with a textbook, but Loher motors has a technical guide online that shows a cross-sectional view of their regreasable motors, it includes an overflow for excess grease as well as a ring to remove the excess grease. It's in german, but as the saying goes, a picture is worth a thousand words.
Allowing the bearing to vent grease is vital. Having heard terrible tails of railway rolling stock wheels screwing off their axels due to hydraulic lock in the bearing grease, its a lesson worth heading.
Thanks for pointing out the german article on greased bearings. However, everytime I download, it does not open, as I think the file is corrupted. I would certainly appreciate it if you would do me a favor and send the file you downloaded, to my e-mail address:
