My highest weight without being prego was 222. I had no problems in tanning beds as far as the concerns you mention. There should be a label somewhere on the crazy thing to indicate weight limit.
I have done tanning beds in the past. The problem I had at my higher weights was getting the color even. I would have white splotches here and there because of the way my fat and skin laid.
I am using the tanning lotion now and I really like it much better. You put it on after your bath. Wait three minutes and then dress. The one I normally use is the Oil Of Olay Touch of Sun. Today I tried the Target brand and it seems to work well too--I can already tell I have some color.
I won't do tanning beds anymore. My 38 Y-O cousin died of skin cancer two years ago.
