I really like the tile! Beautiful. I'm hoping that the tile setback on the sides of the vertical portion is enough to keep the water from wicking onto the stone. Water tends to spread out as it runs down. It doesn't really go straight down. I could have seen the tile going back to the pool coping on both sides. I'm no expert in this area but it's something I've seen happen on builds. I'd be very curious to see how it looks once the spa is overflowing. However, it's an easy fix even if it happens after the pool is full since it's all above the waterline and on the sides.