i say do the first half in 1:25 on the dot. that should feel easy for you based on the long runs you've done. especially if you're rockin' the super shoes. then maintain the pace til mile 20 or so and if you still feel good push down the throttle a little bit.
it seems like gel-frequency recommendations change often and are pretty highly individual. the last marathon i ran i tried to roughly follow a one-every-45-minutes schedule. the problem is that they start to be gross by the 3rd or 4th one. it's not great that you haven't used them on your long runs. some people need to baby their stomachs - hopefully you're not one of them. personally my stomach can handle the gels it's just getting them down that's the problem. also i disagree with poster who said gatorade is harder on the stomach. gatorade is my saving grace in the second half. goes down easy and tastes good. definitely hit up the gatorade stations in the second half at the very least. realistically you'll be lucky to get down half of what they give you in the cup unless you walk through the station.
I keep saying it, but I really can’t tell you all how much I appreciate all the advice! It’s all so helpful. Yeah, I really should have practiced with the fueling on long runs, but I’ll definitely see how it feels on some shorter runs over the next week or so. Thank you!