You have to be your own guide here. I see a round primer, no cratering, no pressure.
Surely others on the net have been down this road, but you have a new powder to deal with.
As pressures increase, edges of primers will get flat, lettering on the case head will thin, then possibly cratering of the primer, and increased lift in bolt during extraction.
One issue you may encounter is premature difficult extraction, is your chamber a SAAMI chamber or a CIP chamber. If your chamber is not set up for Lapua brass, you will have issues sizing down the brass for smooth extraction.
By cutting off the top of a 6 BR small base sizer and using the bottom of the die to size the web with, maybe a great help.
For example, Winchester brass may measure .466 in the web, and Lapua .472....If your chamber was cut for a .466 dia brass, you are in trouble, just have not found it out as of yet.
Chambering reamers should be ordered for Lapua brass(CIP)somewhere in the .4735 area when Lapua brass is going to be used on a custom build. Norma brass causes some of the same issues.
Lapua brass will take a lot of pressure, you just have to know the issues of the reamer vs the dies.
I would not assume anything, work up on your powder charges, carefully and shoot for group.
As brass reaches the elastic limit where the primer pockets start getting loose, this is a for sure indicator that you are reaching the thresh hold of what the brass will take in terms of pressure, no use in ruining good brass.
I have found this Neil Jones decapping tool extremely effective in de capping brass and sorting brass that have loose primer pockets and various stages of primers getting loose, I consider this priming tool a great investment:
http://www.neiljones.com/html/decapping_tool.html
I have loaded for a lot of wild cats where there is no loading data, blown primers where the anvil of the primer can get back into the trigger can ruin a hunt, not to mention gas cutting of the bolt face.
Your new powder is a good one, and I would not rule out R#17 either. Primers choice and OAL will play a significant role in dialing in the load to shoot bug holes, and those 80g really carry the freight way on out there.
It is often that I have found that as you increase your powder charge, velocity will flat line, then start increasing again.
Lot of fun playing with a new wild cat, every barrel is different, your lot number of powder is different, so you have to be your own judge. You will have be willing to sacrifice some brass in loss of primer pockets to play with the upper limits. The main problem that I have found is that some are not willing to toss in the trash loose primer pocket cases. This is a major mistake as it will cost $200 to have the bolt face welded and re machined...just toss the brass if there is even the slightest question.
As we all get focused in on velocity, accuracy will trump all. Sure, 200 fps will mean a lot at 600 yards, but at what cost. IMR 4831 maybe a great powder for this bullet, maybe R#26.
8T barrels do not last long in this caliber, and your first barrel will be sacrificial in nature, enjoy the trip, keep good notes on everything, and be safe.
Best wishes
Good luck!
