You can infer it from the tech. grade. Like E4 5b will be loose, scary and poor pro but E4 6b will be one hard move with bomber gear at your waist.
For instance I've apparently climbed E3 5b (according to the 3rd ascentionist) but failed on E2 5c which suggests I am OK with scary runouts but weak.
Andy Burham once told me (right after leading it) that p1 of Japanese gardens was E4 6a.
hardly bad pro on that rig...
My understanding of the mirky english system is that the E rating can reflect EITHER the sustainedness or the quality of the gear...the second number is the actual technical level of the hardest move...how to understand which thing the E represents is a mystery to me...
The idea is that it requires the same difficulty overall to lead a well protected climb at a harder grade as it does to lead an easier but scary climb so they get the same E grade. Like it's as hard to climb an unprotected 5.10 as it is to lead a well-protected 11.
You can see this in practice when people say they climb 5.12 on bolts but 5.10 trad.
Beacon is sooooooo representative of hard trad climbing The hardest climbs there are probably E4 or E5 on a scale that goes to E11...
Tricams and nuts (and hooks for that matter) are placed regularly on the world's hardest trad routes. The pro for Master's Edge is one Friend and one Tricam.
Learning not to hang while/after you place screws will make you a better climber. Hanging while placing screws will prevent you from advancing. You can make WI6 into WI4 by hanging every body length, but you'll never be a WI6 climber if you have to do that to get up a 6.