I have about 5 small tiles along the top of my infinity wall that have dislodged over time and 2 recently from the hurricane. Can someone recommend a spot grout product that would work ? They are small i'd say 1x2? tiles. I have extra tiles from my pool build. So i can cut and replace single and double glass tiles. Just need to figure out best product to adhere to the wall? Anything else i'd need to put behind it? i realize I'll need to get a grout pen or something probably as well.