I'm not a big proponent of dex like I once was many years ago. I also don't think a 3 count on the dog's skin is optimal for the dog as that's basically dehydrated, bigger dog or not. I've usually always had the bigger dog, and it didn't require having a 3 count on the dog to do so. I certainly don't think dex hurts anything when used as you described. I do believe that giving your dog dex at different points of the keep is a good idea. That way you see if it has any effect on the dog in a negative fashion. The same can be said simply by giving him some dex and then looking at said dog.

I also agree on looking at the dog at close to what I think the dog's optimum weight should be. After doing that, I decide what to do weight wise. I don't bulk the dog back up 3 or 4 lbs above pit weight as that's simply extra weight for no real reason.

I don't use any hard dog food in keep whatsoever. I don't use any RF1 any longer either, though I do think it's a good thing to use if someone wants supplementation in their diet. If you lost when you didn't use dex, it had nothing to do with the dex.