Codeswitcher's Hackerary

1) What are the per-user maximums for:

a) Number of grantees?
b) Number of filters?
c) Number of tags?
d) Char length of usernames?
e) Char length of tags?

2) What are the three levels of NSFWness or whatever that feature does, "anything (show all content)", "safe or non-explicit", and "safe for work only"? Wait, is this the same thing as "Age Restrictions"? (I think I may be about to get offended. Is there controversy about this?)
a) Does it map to a setting per journal or per comment?
b) "Ratings" right? Is there a ratings icon? (Otherwise I'll just use the letter "R".)
c) Is there some abbreviated version of those lengthy descriptions? I need some concision in this interface.
d) There is no "NSFW only" option? Nobody wants porn filters?

3) "AND" tag subscriptions? Really? Are there people using this? Because it adds a lot of difficulty (to say nothing of confusing the poor end users) for what I suspect is not going to be a popular feature. I'm ready to be wrong, of course. But it would be great if we didn't have to support this.

4) I'm contemplating the extant filter management tool, and a current limitation is that you cannot subscribe to different tags at different Ratings levels for the same person. So, if you want to sub to Rhonda's snarry and wincest filters, but: (1) her snarry stuff is really explicit -- NSFW -- but it's no problem for you because it's pretty 'nilla, while (2) her roy/roy alternates between really dark h/c but not always, and you don't want to read the torture but do want to tune in when it's not triggery. So you want to sub to rhonda:snarry:all but rhonda:roy/roy:safeforworkonly.

The interface approach I'm thinking of would support doing this, kinda by accident. However, will the back end? Because if the back end won't support that, then I should do something to add that constraint to the front end.

Put another way: the Rating filter seems to modify the user, not the tags.

Which is a round-about way to say, I think I'd better have some idea how subscriptions are represented in the db. I was imagining a three-column hash table, user_id/tag_id/rating_id. Except maybe I'm imaging user_id/[array of tag_ids]/rating_id to handle the "AND" case. But in any event, with all three foreign key fields being many-to-many. Which on further contemplation is not what's happening?

5) What characters are not allowed in tags and might be used as delimiters?