I had this on my mates job last year, loads of externals too as they wanted it just half tiling. Did my head in. The trim wasn't perfectly circular, as in one side was longer than they other so they never matched perfectly. Bodged it a bit in the end by tapping the sharp corner down a little. It really needed the trim replacing but it took me as long to cut them all as it did to tile it brick-bond. A free job so left it at that with no sharp edges but not the best look.
Always plastic from now on for me! That is, when I do the odd job. Managed to avoid tiles at all cost this year I think :lol: