I have been doing this same basic procedure as well. I use a Sandvik cabinet scraper to resurface the top of the bridge rathar than sanding. It seems to take less time. Also, I don't take out all of the string groove. My thinking is that the wood has already compressed that far, and should be rather dense there already. It seems to me that there would be a certain amount of compression set into the wood under the string. As Roger says, the epoxy will find it's way around any crevice it can find. I have had it creep from the back row of pins to the front row. Last year I was replacing bridge pins, and did the epoxy treatment to the back row of pins in the treble section. I came back the next day to install the front row of pins, and found that the holes had hardened epoxy in the bottom. So, I had to do some extra drilling that I hadn't planned on. Now I always epoxy the front and back pins at the same time, at least within a section. Roy Peters.
This PTG archive page provided courtesy of Moy Piano Service, LLC