Thanks Bill!
I did end up doing a dry stack over the top and then grouted with a grout bag. I figured if they use it for floors and it’s approved for exterior use, I’ll go with it. The grout bag enabled me to really get in the cracks pretty well. I used a tinted grout and am pleased how it turned out. Here’s a pic of the arch before I grouted. Don’t have one post grout yet…
