Careful application of low volume expanding foam?
The tiles won't overlap the bathtop though
Don't know what "tanked" refers to, and don't quite understand what you want to do there so just ignore me.
You could pack it out with tile adhesive to subtley cover the gap. Might look shit depending on the tile choice though.
@TooTallTim started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Careful application of low volume expanding foam?