You don't say if your using a new gasket or re-using old one. Doesn't make that big of difference as long as you get nice even fit. (If your going to buy a new one at some point...I bought on at RV dealer and found out later I paid about twice what I could get on-line for. Didn't realize at the time so much mark up in one simple item).
Also see
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26045448.cfmIf you have the "new" type with the plastic tabs, "tight enough" is when you can see plastic tab start to compress.
No matter if you have old or new design...In couple weeks tighten again no more 1/8 turn of bolt, to make sure even fit and torque.
Then the start of RV season or when ever you do your annual maint tighten no more than 1/8 turn once a year.
I also wiped down the inside where a couple of water tracks were visible from old gasket leaking and now can inspect with flash light without removing inside cover, just to make sure no leaks from time to time. And lets me sleep better.
Should last many years, until gasket is real thin then start process all over.
(Edit part) forgot to mention. Take it real easy on those plastic air louver things on inside cover. (the little movable fins that direct the air flow). I broke one if mine and was a hassle getting new and putting in new ones.
