+1 on the "digging in" method for horizontal spitters on large rounds. I've used this method before on someone else's unit. Work smarter, not harder. A lot of pieces to be had in a 30"+ round, if I cut it going to find a way to use it. But I do see why some decide not to mess with 'em for their body's sake.
All that said, when looking at splitters one of the first things I consider is the ability to operate vertically as well as horizontally for this very reason. I would also caution on the use of skidding tongs in a lifting situation, can be done but don't put anything underneath you are not prepared to crush (yourself included).
Chainsaw quartering is viable method as well for "hard" hardwood (i.e. oak, S. Maple, etc). Start a cut (with grain) a few inches into the round, through the sapwood and finish with a wedge. Oak/maple/etc usually will pop apart no problem. Softer species may not be worth the effort though as they require more cutting................unless you enjoy making long curly saw chips.