lovely post--but . . . before speaking I'll let some pictures do the telling:

above shot is my sample infected with powdery mildew before dipping; shot below is after trying your technique:

left on some of what you call sugar leaves that had powdery mildew, thinking that would be the quickest place to tell if peroxide really works. clearly no improvement.

jorge cervantes also touts this method and in his 8-year-old video on yute-oob he suggests not just dipping but letting the material soak in the H2O2 bath for a few minutes. he's not as strict as you about sterile conditions.

had different batches going five, ten, fifteen minutes or more and still detect no diminution of the powdery mildew.

though I enjoyed your post, to make it more credible--and jorge neglects this as well--you might inline before'n after snaps of infected cannabis, to prove the mildew really has been removed by the bath.

to give the technique its due, I tried various dilutions of peroxide. jorge agrees with you on 5 oz. per 5 gallons of water--but I tried less and then more peroxide and saw no removal of powdery mildew.

therefore reserving my upvote till more data is in.

"don't care if the results are anecdotal--as long as it's my anecdote. . . . "