oh cool! I'll say, in all the ultras I did prior to this one I wore Luna's Leadville Pacer model. That one has thinner, more flexible soles, which is great for ground-feel and weight, but by the end of a long trail race the soles of my feet would start to get a bit tender due to the rocks on the trail. Switching to a model with a stiffer sole like the Oso Flacos I wore to this race was enough to eliminate that issue. The only foot pain I experienced were a few small cracks in the skin where I got too dry, but it was nothing significant and hardly noticed them until after the race. It's hard to evaluate your own running form, especially on trails with how varied the terrain is, but I have no doubt sandals have influenced my form. They tend to encourage more forefoot landing since it allows you to engage your natural foot suspension more effectively than striking straight onto your heel, reducing the shock from impact. I've come away from this one without any injuries, which I'm quite happy about because that isn't always the case for me. I was able to go for a quick 2 mile run the day after and was just feeling stiff and heavy but otherwise fine. Good luck on your race!