I'm not a restorer, but I follow the techniques and have been lengthening my foreskin. 8 hours is the magic number. For those who manually restore it's the most difficult and near impossible to make gains as the most time seemingly spend is one hour and it's basically the same exercise masturbating.
With the TLC, wearing the device is a chore, but you will see results. With 8 hours a day, one day off a week you will gain anywhere between a inch and a half to 2 inches of consistent routine. You also experience dry skin with with skin tissue expansion. Look at the accounts of women with breast augmentation and recovering burn victims. With dry skin comes tears. With tears come infection and down time. The only thing around this is prevention. Avoid lotion. More pure forms of cocoa butter and shea butter you can rehydrate the skin. Once stretch marks are there, nothing will work topically to reduce the tears. Avoid olive oil. It does nothing. Some idiot-troll on the foreskin restoration board recommended it, but there is no evidence or studies that show any proof it works. It was the life blood of villages who used it in everything from cure all cures to rubbing on pregnant women to make the baby grow up strong. Worst yet, extra virgin olive oil isn't pure. It's filler with cooking oil and can cause infection from clogged pores. Using proper hydration of the skin will reduce possible chances of skin tears. Use the cream on the sixth night after restoring and taking off the device. The morning of the day off you can use a retainer as you can every night and use the cream. Showering the night off and morning after will reduce damage and slippage while wearing the device. Never let the device be compromised with creams or oils. It will destroy the silicone.
As for the duel tension devices, this I felt is the most uncomfortable, but also the most effective. It is extremely hard to wear the device with proper tension for optimal foreskin restoration. A technique I found helps is wearing the device for 6-8 hours as you would with the TLC and switch over to focusing on the inner inner foreskin and mucosa membrane. This will allow better blood flow and focus on area of tension. I experienced slippage, even when washing the device before and after adjusting using alcohol. It also allow continuous restoring if one is injured due to overzealous over tensioning to chafing against clothes. You get 12-16 hours and you don't exhaust the body tissue which can happen when you have slippage and readjusting of the device for dual tension and thereby causing sores and skin breaks. And you feel you are getting the hours in at your mind can deal with, but skin tissue is bruised and blood flow restricted.
As you are aware, the growth doesn't happen during the wearing of the device. It's when you are on the off time. Few things allow mitosis in the right environment. To accelerate growth it's on the experimental. You have Papaverine which can be injectable or topical in a cream form, but you need a prescription from a doctor and a handful of companies hold the patent. You can go to a compound pharmacist and they can make it for you. I wish there were more secrets to uncover, but it is time and consistency. It is fair practice of preventing injury and proper time off.