The short answer is yes. I'll ride 8-10 hour days on a few week trip without issue. The long answer is that, there's more to it than just the highway pegs. TBH They could be longer, but cutting the traction in them helped a ton.
The only sage advice I have for long distance riding is to pay attention to what hurts and change the bike (or your body) accordingly. Sounds obvious but pay attention at
speed. On a new bike, I'll get going at my comfortable pace and relax my whole body to see what changes. Do I fall forward? Am I getting pushed off the bike by wind? Do my feet fall off the pegs? All that stuff is tensing your body up. I have the Ss so fine tuned I can set the throttle and just float on it, no hands, no feet, just glide against the wind and steer with my weight. Pretty fantastic TBH