Seamless tile to drywall transitions.
Wall tile to baseboard transition.
If you have tile on the wall this serves the same purpose as baseboard.
Then i would use cove base tiles for the wall to floor transition.
Cut a 45 degree angle on one end of a piece of baseboard that s long enough to make a full length piece.
Not sure that just cutting the baseboard at the tile is attractive it looks like it is unplanned pic 1 cutting the baseboard flush with the wall the tile is on might be an option but is that really acceptable.
I almost wound up taking a dremel to shape out the vertical pencil tile where the edge of the subway meets the wall because it was just a tiny bit thicker than the subway tile and baseboard but the crown was flexible enough to fit right over it without trouble and the resulting gap filled easily with caulk.
In these three following pictures you can see the large wall tile going in.
It is more work but i would remove the vinyl tiles in the areas where the gap exceeded the width of the base of your cove base tiles then cut and install new vinyl tiles for these areas striving for a 1 8 gap all along the wavy wall.
In general baseboard finishes the bottom of the sheetrock and protects the bottom of the sheetrock.
This bathroom received new drywall 1 2 over both the left and right walls.
Pic 2 maybe a slight bevel to transition the baseboard to the tile would be ok.
Measure the longest wall from end to end and note the measurement.
The tile measures 18 x36 and is 3 8 thick.
Grout is only used to fill the joints between tiles while caulk can seal seams in many spots along baseboards and crown molding on windows to stop leaks and drafts and anywhere two.
Make the cut on a miter.
Pic 2 maybe a slight bevel to transition the baseboard to the tile would be ok.
I wouldn t use any baseboard if tiling the wall.