[ossiblue]

Couple of pointers, if you don't already know. As you found out already, when doing walls that are adjacent, it's important to make sure the surfaces are level (to the counter top) and vertical to each other where they meet in the corner. You may have to make some pre-setting adjustments to square the corner and be certain the counter top is level.

Also, plan ahead on how you are going to cut the tile to fit the lengths. Can you fit a whole tile row at each end, or do you have to make a narrower row somewhere in the field to get the pattern to fit in the length? Sounds like you are using small tiles on a netting, so the trimming for fit may not be that difficult, just be aware.