I think I found a concrete answer to the “how much is too much” part:
“By the time it reached the Titanic wreckage, the Titan submersible would have been facing a pressure of between 375 and 400 atmospheres.”
What COAL did you end up with? I think I would try Nosler’s preferred, the 63gr and see if it performs differently. If not, switch up something as mentioned above.
Edit: just saw your post above. That’s where I was going with the COAL question, but I also think that since Nosler got best...
I would just try some loads that are in the Hodgdon manual and use a starting load of something with the lower PSI. Leverevolution and 3031 are pretty good powder for low pressure to velocity ratio. You can reduce 3031 also, but not sure you would need to for a hunting load and I would find out...
I'd just load your own 180 ttsx loads if your rifle already shoots those well.
Barnes doesn't have the preferred load on the data sheet that is on there now, but the older one from 2017 had Magnum as the best shooting powder for the 180 ttsx in the 300WM.
Here's my argument for the RUM. It is a much more efficient way to spend more money than you need to for a high-power 30cal when you could just go with 30 Nos. or 300 PRC.
I usually check mine when I’m get started on doing my charging, or if I’m changing to a charge > 20gr +/-. That way I always know my weight is consistent.