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I actually saw your suggestion, and I have been pulling a bunch of 6-0s and 5-0s with Lum double dance Groudon. I do run Xatu with screens to aid in setup if I need to. It really works well.
I still use Pressure on all of my walling Ho-Oh sets, but I use Regenerator on my offensive sets. It doesn't switch out very often, and Pressure is extremely useful for stalling out low PP moves.