The rig tune pro is good to about 1100 lbs. On my single spreader I am running close to 1000 lbs on the uppers and about 700 on the lowers. If you have a double spreader you can get away with slightly less as the rig is less prone to falling off in heavy air. I find the Loos gauge to be a better deal just because it can go higher so you aren’t as close to the max load possible.
Interesting that you brought this up. I am in the process of replacing my halyards after 3 years of racing. I am going with the V-100 for both the main and jib halyard and Endura Braid Euro for the two spins. All in 8mm or 5/16. I had V-100 for the main for the last 3 years and it has held up pretty well to constant abuse. The end is getting some fuzzing. I always sky the halyards after every use to protect the core. I have them stripped for about 20ft to reduce weight aloft. For my new halyards I am adding dyneema chafe guard to all the ends for additional protection from the sheeves.