I do the LSPV last. My order is right rear, left rear, right front, left front and then LSPV. I use a Motive pressure bleeder. Dunno what to say other than keep bleeding until no air comes out. I've always wondered why it can be tough and think it depends on the position of the LSPV. If you push the rod up so that you get maximum rear flow then maybe it's easier than if the rod is cutting off fluid flow and you get a pocket of air stuck behind that is just trickling out. I have no reason to believe this other than just a hunch.
"Silent enim leges inter arma." -- Cicero