Use them, and tell us what happens.
I know that with a double-overhand deadlift grip, you want to grip the bar with your calluses above the bar, so that the bar does not pull down on (and potentially tear off) your calluses during the set. However, when straps are being used, does the same principle apply, or is it permissible to grip the bar with your calluses more directly on/beneath the bar? Based on my (extremely limited) experience with straps, it seems that maintaining a callus-protecting grip leads to a looser grip on the straps, whereas the “incorrect” grip (incorrect when used without straps) allows for a tighter grip on the straps. After all, with straps there shouldn’t be even close to as much pressure/friction on the calluses, right?
Use them, and tell us what happens.
Based on using straps for one light set and one work set, here are my impeccable and absolutely indisputable findings:
It seems like using straps does indeed decrease the pressure on the calluses when gripped “incorrectly,” not only because there is less strain on the grip, but also because the strap provides a bit of padding between the calluses and the bar. That being said, I still felt the bar pulling on my calluses a bit throughout the workset. I didn’t try to use the straps with the “correct” grip.
So I punt, haha. It would be silly to emphasize my one-time subjective over the knowledge of others. Rip, I would imagine that you have a correct answer in mind and were merely hoping I’d figure it out on my own. If you wish, I can try the other grip on Friday and get back to you, but if it’s all the same to you I’d prefer to just listen to your answer and follow it!
In a tension grip, if the straps are used correctly there is no stress on the calluses. It's all on the straps and the hands below the wrists.