Although we aren't particularly seeking a bigger LS, I would like for you to look up my linkshell and give it a try. It might be for you.
We're Cynosure. We have about 30 members and typically have about 15 online on weeknights, perhaps 20-23 on weekend prime-times.
We have a large share of come-backers and new players, but about half of us are veterans with multiple 75 jobs.
On a personal note: I admire your wish to help out (or so I infer from your saying you "can't promise much), but you mustn't worry too much, at first, about getting more help than you receive. In time, if you stick around, I have no doubt it will be you who is helping another newer player, or several.
Anyway, take a look: http://www.cynosure-online.org/forums
I can also recommend some other fine linkshells, if you'd like to "shop."