I've tried pretty much every climbing method legal to use on public land, and I settled in on fixed aiders on each stepp made out of tubular webbing. I'm 6'3 and find it's easier not to stretch it too much. I strap each stepp at chest height, use a linemans belt, and head on up. I've stretched 6 stepps to 30' before. They easily and comfortably get me to 22-24' even in bulky clothing without overextending. I fit 6 stepps with aiders, and 3 without (4 if I know i'm going to be on a big tree) for my platform. I have the 12 stepp bag and it all fits in. Extra 2 minutes at base of tree setting up the bag for my original ascent, and an extra 2 minutes at the base of the tree packing them in neatly. I also tie the loops around the main leg of the stepps, and lay over the crossbar. Makes me feel a little better. Hanging from just that bar would spook me, though i'm sure it's fine.
A nice dual purpose tool too - you and a friend each using a stepp with the aider around a deer's neck makes a great dragging tool. Girth hitch around neck, grab crossbar and start dragging.
I've tried the aider from Wild edge, but haven't gotten to a level of comfort yet to see it being easier and simpler than individual aiders. This is an interesting set up though, i'll probably give it shot over the next few weeks. I keep all my methods in the truck. It seems like certain setups go well for certain hunting circumstances and individual trees. I like to be prepared. nice work coming up with a great method.