I don't think you need to sustain a stretch for 30 seconds to get the results you're looking for. There is another take on this--that short (3 to 5 seconds) very intense pulls is enough. And it's easier to sustain short pulls for a longer period of time as you increase the strength of your grip.
Your grip does get stronger with time and the talcum (or baby) powder does work well. You can also get those cloth gloves at the pharmacy, which come in boxes, a dozen or so per box. They're pretty cheap and you can reuse them if you get lub, or whatever on them.
I don't ever get that close to the glans that I chape, scrape or burn the skin on the head of my penis. In fact, I keep my grip at the circumcision scar or below--that's a couple of inches (or at least an inch), down the shaft from the head. If you're uncut, or you have lots of foreskin to play with, so that you can reduce the direct impact on those sensitive nerves, then that's different.
I injured those sensitive nerves in that area once and I don't want to repeat that kind of injury. It put me out of commission for many weeks until that nerve healed.
Err on the side of safety, as always. You only have one dick to work with. So be kind to willy--especially his head. Use YOUR head.
If there's any pain there, stop. This should not be a sharp pain-filled experience. Stretching pain is one thing. Any sharp pain is a signal to stop and rethink what you're doing.
Easy does it!! Give time, time. Rome wasn't built in a year. Etc. etc. etc.
If you're unhappy with the size of your glans, that's what ma nature gave you. Deal with it. I don't believe there are many success stories out there regarding enlarging your glans. In any case, I think that is for people who have been at it for some time. I would love to read about a success story in this regard.