I have ridden my pulk on both Denali and Vinson. It's not such a great idea
On Vinson there is a long, gentle slope above BC with a mostly straight track. In later years there are some crevasses near the side, but it's mostly straight. You can really fly down here, which means you can really hurt yourself, which would be really bad in that location, so only an idiot would do it. I did it, but at the time I was more worried about the 20kg bag of half-melted human shit (mine and my partners, I lost the bet) on top of my sled. It was good to wrap my arms around for added security, but it was kinda squishy (sorry Squishy!). If you're sled is at all packed high, there is a chance of turning over and this is bad. You only get less than 1km run, and the route is more than 10km along the glacier, so it's really not worth it.
On Denali, on the lower Kahiltna, if I recall correctly there was only a couple of sections that were OK for it and in the big scheme of things they were so short it is not worth devising any system to try to make it better. Spend your time training to pull the sled rather than ride it. Depending on the year there are also some really big crevasses beside (under? across?) the route so you would not want to go off-course or tumble and roll off the track, or hit the snow at speed, breaking through etc. Given that you would be on or near the track, on a mountain like Denali there is a good chance there will be other climbers on the track. They should not have to get out of the way of some idiot trying to ride his pulk down the hill, or be hit by pieces of that idiot's old green ice-axe flying through the air because his braking system blew apart at the first use. You would have to ride off the track, increasing your chances of going into a crevasse, where those climbers would probably decide to leave you, figuring any idiot who tried to toboggan his bulk down a crevassed glacier was too stupid to live amongst them
Unless you trial it in the Alps, which would also be a very bad idea, I doubt there is anywhere else where trialling it on snow will replicate the ice of Denali etc. so your braking system may not be viable. You could, on the other hand, spend that time in snow by learning to ski