I'm not familiar with the options at UB, but Full Tilt lets you filter and sort tables by pot size and % of players seeing the flop. If UB lets you do the same thing, then just filter so you can view only the tables that are both loose and wild, sort by %-players-see-flop, and try to join those at the top of the list.

I also color-code my villains when I create notes -- green == fish. If I see a loose+wild table with any villains color-coded as green, then I try to join that table immediately.