Going to re-tile my bathroom, tilling over the existing tiles,at present it has a plastic bath trim on ,the type fixed before tiling. I have cut it off, not really sure as to fitting another one before i tile or using silicone to join along edge of bath. bath is a plastic one but soundly fixed and very little flex in it. I favour the bath seal, as my escapades using silicone are not good, should i decide to use the silicone do i leave a gap between bottom of tile and bath, if so what size gap do i leave.