I have run both a 2 inch and 3 inch lift on my 110s, with a far amount on the roof rack (about 150 lbs on some trips).
The more weight up top the more careful you need to be, but overall I'd say it's not a huge safety problem if you drive sensibly.
I would recommend going for a heavy-ish spring set up. A light or progressive, but longer, spring will make you seasick when overlanding (but feel awesome on a technical trail) and a RTT will aggravate the issue.
Good luck.
Cheers
Ray