Gap around sink - how to silicone before tiling?

Hi, (sorry if this is the wrong section)

This cloak room is becoming the bain of my life....!

I have a 550mm wide vanity unit and sink, and have had the pipes boxed in to (almost) suit the size of the sink, which overhangs the unit by about 5mm each side.

Here's a pic of the vanity unit, not quite installed, but in the place I expect it will end up:


And this is one with the sink on top:



The back is against the wall, great, the gap on the right isn't too bad, probably about 12mm, but the gap on the left is just over 20mm, which is the one that concerns me.



As you can see, nothing is square - the gap narrows to about half at the front.


My plan is to tile around the back and sides with 9mm tiles, but having never tiled before I'm not sure how thick the adhesive will be. Ideally, I'd like to seal the between the sink and the wall with silicone before tiling, but I think some of that gap is just too large and it will all fall through.

Options that have crossed my mind are:

a) Fill the gap with expanding foam, slice it off just below the level of the sink then silicone over that, tile - hoping that the thickness of the tiles and adh is enough to bring the face of the tile close enough/overlapping the edge of the sink so I can silicone around the join

b) Same as above, but using thin wooden strips instead of foam, screwed to wall then siliconed over, basically using the wood to stop the silicone falling away.

c) Some sort of 90degree plastic strip stuck to the sink and wall, and tile over that. I tried this today with something I found in B&Q but it looked a bit naff.

e) Not worry about sealing the gap, and just get the tiles on! (perhaps use temp nails in wall to stop tiles from slipping down), and hope that the width of the tiles and adhesive is enough to bring it out far enough over the sink,

f) Another thought i just had now, to make sure the tiles are thick enough by backing first with some cheap plain tiles and tiling over them?

g) Something else?




Before suggesting option z) Get a "pro" in..... I tried that route for about 9 months, and they've either screwed it up completely, and I had to redo it, not turned up, or don't want the job in the first place, so i'm on my own . I've made reasonable progress, but stuck on this part!

Any thoughts appreciated, cheers!

 

Hmm, interesting, thanks! Can't find any online, so might have to get 10m of the stuff from amazon, but definitely an option, cheers!

Sorry

Just out of the picture, bottom left, is a skirting board stopping any further movement to left - I hadn't planned on removing that as I usually end up making a complete mess of the wall... I could slide the sink over to the left a bit, but SWMBO wants it right in the middle of the unit (and also doesn't want skirting removed). Not a bad call with the shelf though, thanks, I'll get the CEO's opinion on that later.

Thanks for your advice!

 

Ooops, I meant - I can't find any in SF or in the sheds, so will have to get it on line!