nobody :(

I just started using UCAN two weeks ago for my long Trainer rides (so 2 experiences with it).

So far so good. I took a full serving (in 10oz water) 30 minutes before my rides. I also took a concentrated serving after ~75 minutes (my halfway point) in only 4oz of water and it caused no GI or other issues, so I think you would be fine only 15 minutes before, or even as you are starting a ride. In 4oz it is almost a gel, but still went down quite easy. Taste is kind of muted in the flavors I have tried, which I prefer to a strong tasting product.

I used it as I would any drink and sipped as needed. I did some longer workouts with a 1 scoop in full water bottle appx an hour before.

Since the testing time I have used it in 1 1/2 IM race, and didn't have as good a result as during training. I was at a much higher effort level, and although I had absolutely no gastric issues, I felt I was a bit short on fuel. Could be user error on that front, but I found it a bit hard to drink at high intensity and the thickness didn't feel right. I'm sure I needed more experimentation, and my original purpose was for IM intensity, but went with it for 1/2 and likely would either tweak it or use something else in my next.

thanks. I dont plan to use during races but thinking endurance rides and pre race. as a road racer probably could for some of the longer ones

I would agree that is a good plan. I found other things worked better for me at race effort.