I feel like as long as your characters are close to max level, you don't need to stall too much. You basically need to stall for as long as the stage allows you to, with the exception of the turtle and the blue or purple baddie on stage 4. If you do that, then Usopp the minute you get into Ivankov, you'll be at like 14-16 turns without taking a single hit from Ivankov (just the 6k special / turtle hits, not counting any meats you've encountered). Then after doing 3 rounds of attacks on Ivankov, use Perona/Smoker and take him down to 30%, then release the hounds / specials.