My heating pads never got hot enough fast enough. They were also kind of awkward to bend around my unit, and if the pad wasn’t in contact with my skin there was little effect.
I find that my rice sock gets plenty hot. I start my sets with a good 3 minute nuke, and then go 1-2 minutes for successive sets. Sometimes it gets too hot, and I have to put a piece of cloth between it and my skin to prevent burns.
If your rice sock can’t hold the heat for more than 10 minutes, could I suggest maybe adding more rice and/or starting at a higher temperature?
To each his own. Maybe an IR heating pad would cause me to switch, but I don’t feel like forking out the bucks for one right now.