Okay, a drop in might be weird. Honestly, I don't know what I'd do. I mean, here, my biggest worry was when we trialed in dirt. I know if the dirt affected his natural running/striding, I'd probably not choose that venue anymore, no matter how nice it is. However, if the majority of your trials are going to be indoors, it may be good to get them used to it. I mean, I see Edan's (and CJ's) runs and they look like they're fine on the mats. Could be just a matter of getting them used to it? Not sure. Also, other venues may have better matting.
Sigh. I say since you're signed up, go for it. Try the tacky stuff and see if it helps. If that works, awesome! If not, well, then you have to make a hard decision.
If there is no fur on their pads already (as in you keep it clipped), I'm thinking cutting more isn't going to help. I mean, I get the scissors in between the pads to cut the hair to below the pads, but it sounds like you're doing it well enough. Bummer!!
Good luck with whatever choice you make. Or just come to CA, we could use more dentists, lol.