I fitted my new insoles into my Alpine Stars Ridge boots. First obvious thing is the Gerbings are thicker than the typical insole in riding boots. Makes for more cushion, particularly in the heel area. I got lucky and mine did not require trimming. Note, you can only trim off the toe area, nowhere else. Order the size Gerbings recommends for your shoe size. You can barely see this in the picture above, but there is a 'bump' in the middle of the insole under your instep, not sure if that's an intentional arch support (not quite large enough) or where the junction of all the heating wires are, but I suspect the latter. Note you cannot feel any wires at all, just fabric covered foam. They feel comfortable, but will take a little getting used to in a postive way. The thicker cushion is mostly at the rear half of your foot and you seem more tilted forward when walking. It will depend what you're used to.
Now for the electrical... Note, I could not do a real world ride, so this is just me standing out in the cold. For the test, I plugged them in directly without a controller to ensure full heat. It took 5 minutes for them to warm up, and full cook takes a bit longer. I had cotton socks on which may have insulated me slightly, but these things will not burn you. The heat is uniformly distributed all over the bottom of your foot. You do notice there is no heat on top of your foot. While I did think they got a little too warm for comfort, I suspect you'll have your controller at 3/4 in the cold weather while riding. I will update in a month or so when I can get some real world riding in.
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