If you can draw at a pace where a few pages a week is sustainable (or draw up front or whatever the case may do) I think definitely go with that option! A lot of folks can only manage 1 page per week so you'll already be running laps around them lol.
The other consideration to posting to a place like Tapas is that one of the main ways people can stumble into your comic (especially at first) is by finding it in the "Fresh Updates" tab. A comic appears here once every time it uploads (but only once per day, so if you upload 2 pages in a single day it wont bump to the top the 2nd time). In this way, by only posting once a month with a full chapter you lose out on a lot of potential visibility- you only appear on Fresh once rather than 4-8 times (or however often a week you would post).
This is also the answer to:
Generally speaking, avoid doing this. This is undesirable for a few reasons:
1.) editing an episode and adding pages doesn't put you back on Fresh, so you might as well just post the 1 monthly chapter if you were going to do this.
2.) Your readers don't get the same kind of notification for edited episodes as they do for fresh ones (even if you click the notify subscribers button) so some people don't bother checking edits! This can lead to potential confusion. There was a thread a long while back that had discussion about this:
So in your case, either doing "part 1" "part 2" or "Chapter 1 pages 1-3" or whatever you decide on would be better practice. Another thing to consider with Tapas at least is that episodes that get toooooo long can be problematic for some folks, as neither the website nor the app bookmarks how far you got into an episode like Webtoons, for example, does. So if you post a 30 page update and someone only has time to read 16 pages and then has to close out, next time they return to your series they would have to scroll and scroll to find where they left off again ;0 Not the end of the world, but something to consider.