Regarding skid selection, floatation, and wheelie control: no skid, stock, aftermarket, whatever is going to float well AND keep manageable ski pressure if you have an aggressive track and/or you weigh too much for the track length. You can get wheelie control with a coupling skid though.
One of my riding partners is 280 lbs and rides 160 length tracks. He had a stock pro with a 3". Trenched to china everywhere. Flipped over backwards a bunch too. Then boosted Axys with Kmod and conquer track. Trenched to china everywhere until the track got so soft that it was basically junk. Then he floated quite well. He could carry the skis uphill and not just flip right over backwards though. Now stock alpha - trenches everywhere and excessive wheeling. He just shortened the limiter strap to fix it and now it has annoyingly heavy steering. He needs a 174, plain and simple.
I have personally ran stock Pro, stock Axys 800, stock Axys 850, two Gen II Kmods, and a Gen III kmod. The stock skid with factory springs has a great balance of ski pressure and floatation for the 2.6" track. I'm 235 lbs. Pro with 155 3" and kmod - trenched terribly but once I got moving it would settle down. Boosted axys 163 2.6" with stock skid, good floatation but would wheelie over backwards quite easily. Then gen III kmod - good floatation once tuned in, and wheelie control. Fully coupled I could not loop out no matter what. Now stock 850 163 2.6", good floatation and i don't have enough power to have wheelie issues.
You need to get the right track and in the right length if you want to have good floatation with reasonable ski pressure. And then if you're making big power and can't maintain your ground speed (most can't, especially boosted), then you will benefit from a coupled skid. But putting a kmod or other coupling device under a 155 3" when you're 200+lbs isn't going to work well in deep snow or in the trees. Lastly, aftermarket skids take time to dial in to get that balance of floatation and ski pressure. Subtle changes make a big difference, and that goes for stock too, but thankfully they come from the factory pretty darn close to perfect!