to give my thoughts on the subject:
the two dog play is a very logical one, from a money management point of view. it is the kind of play that gives you a decent plus when you split, a huge win when you hit both, and a small bearable loss when 0-2. 3 dogs changes the $$$$ aspect of it, and 4 or more is really pushing it.
this also falls in line with avoiding totals, where you need a 55% success rate just to break even, much higher if you get into -120s and the likes.
needless to say, you still have to pick your spots, and that may mean not having a play every day. luck is not a consideration here, as it works both ways, for dogs and favorites.
i don't follow xerri's strategy, but he? is among the leaders in the sunday contest, with a very nice percentage return on money risked (about 33%). can't beat that.
pep