Well, depends. Maybe 2-3 reps a week at/over RPE 9 for an intermediate. Beyond intermediate shit gets more complicated with tapering, etc. This is assuming the lifter has a solid valsalva and isn't spooked by heavy loads, etc (iow, they already have a base of essential "strength skills").
Well, and intensity, of course, too. A 12 minute density block with ~70% 1RM will look quite a bit different from a density bloc with 80ish%.
I've sorta tweaked my approach since that 2015 quote Eric posted. What I would try to do now when setting up an density block is fiddle with load, time and target reps so that I'm getting very close to my known ~48 hour "max recoverable volume" at a given intensity. For OHP, yeah, I set my target at about 25 reps in 12 minutes now using about 77% e1rm (the quoted 7 mins just wasn't enough time to get the MRV).
I should mention that I don't like this approach for deadlift or back squats. I don't like feeling rushed with those lifts. Front squats and press are so logistically easy that they work well with density blocks.