I'll cut big trees, not afraid of em the least bit. I employ a timber carrier and a strong backed cousin to pack the rounds into a trailer. The trailer has either a low step or a fold down ramp which make loading quick, easy, and fast. We can roll the rounds out near the splitter, and use the timber carrier again to pick the rounds onto the splitter. Or, we can bust the rounds in half with a maul. Its not that difficult really... the trailer sure does get full faster with the big wood.
As far as saws go, I laugh at 50cc saws. Sorry, I tried 'em and didnt like em. At low elevations (6,000feet) they run okay, but still I won't pull anything bigger than 16" with em. A high elevations... I really don't use them for anything big knocking limbs off...
... which brings me to my next thought. Why on earth do I want to set down my falling saw after the tree tips over? Because as soon as I knock the limbs off, I need to buck it up. And there isn't a limbing saw in the world thats going to buck up a 24" doug fir at 9,000 feet. Well, maybe my 372xp... and it sure makes an awesome limbing saw, its got power to spare... and is all warmed up cause it just tipped this big ole tree over.
Now if I got my wish, and had a 395xp to drive whatever bar of my choosing, I can see having a smaller limbing saw. No one wants to swing a 20lb saw around blowing off little limbs. But I just have a lust for a big saw to pull a bar with extreme authority, its really not needed. A 70cc saw... its about perfect for all around firewooding. It will pull 24" bars with full comp well at my elevations, still light enough to allow for a tree to be limbed and an operator to not be fatigued.
Now, my cutting is probably a mile higher than you are. My saws run like arse because of it. No replacement for displacement. I also only get to cut dead and down trees, conifers, and that leads me to Douglas Fir. If I wanted to pick and choosey about the diameter the rounds are... I'd still be cutting firewood. Or rather, driving around the mountain looking for little dead trees.
Different strokes for different folks.