Jim, hope you don't mind a side thought in with the pad selection. Its about comfort.
Anybody use those bolt on platforms that support your feet? Wonder if they make them more stable and comfortable in terms of shifting?
I heard from a guy that he takes plywood in a small,rough boot shape, cuts a spacer to the stirrup thickness, and makes a plywood/ spacer under heel-stirrup-spacer under front of foot/ plywood sandwich. He said that they work for a while until they get too wet. Then another quick and easy screw-together platform is made for each. Cheap. Not great for standing on branches, but for straight-forward conifer removals, he liked 'em.
I'll bet that the commercially made one's are helpful, too.
BTW, I climb most all removals with pole spikes and basic leather pads, and I don't get much shin discomfort.
Because I got them used ($25 on ebay) the leather straps that hold the upper part of the shank to the pad was a bit worn. I was concerned about them breaking while in the tree, so I drilled the leather and foam (I'm guessing) pad and the shank, allowing me to use a pan-head bolt and large thin fender washer on the inside (against the side of my leg, don't even feel it) and exit throught the adjustable hole to a lock washer and nut. Peened the threads a bit and filed it smooth. No Slop!
I have a second pair of tree spikes, and a pair of tree spikes. I've used the tree spikes a few times, but rarely. I use a choked climbline when I'm climbing, and feel comfortable climbing thicker barked Doug-firs, being mindful of where I am stepping on the thickest bark at the trunk. I can believe that I don't always get purchase into the sapwood, but I don't really spur-out, only few times. For thinner barked trees, they're even better, here: maple alder etc. Just did a second walnut, good, too.
I just wonder if people overlook short spikes.