Clamping - How to progress?

Currently, I’m doing a 3x10 minute clamping routine. It’s fine for now, but I’ve done this exact same routine before with no results, so after I re-condition from my three-year break I expect that I won’t have gained anything, and will need to increase in some aspect in order to gain.

There are a number of ways I could see this going:

1- Increasing set time (drilla used 15 minute sets, juke worked up to 20 minutes per set)
2- Increasing number of sets
3- Increasing tightness of clamp (more wrap, smaller clamp, and/or switching to uli thing)
4- Adding manuals (jelqs, bends, horses, etc)
5- Adding weight (penismith and hobby created quite a stir with this one, but if clamped jelqs [with unquantifiable pressure] are within bounds, I don’t see why weights would be an issue)

Which one should I do, and how ought I go about doing it?

start 6x4.5 -> 7.5x6 goal