I usually tend to put bigger skimmers on smaller tanks because I think manufacturors rate them a little high, so I would guess the 1250 would be fine for a 90, or 100g even heavily stocked tank when the factory rating is for heavy stock 130 to light stock 200g. Most folks using Deltec seem to like them.
Personally, I'd the the AP601 over the turbo skimmers. The AP line simply has more reaction volume. I don't know of many people who use the turbo line.