You got this @Dee .
What I did to boost my confidence is once the tray had set the next day I put some temp pipework off the trap into a bucket . Then gently tipped water into the trap from above . If no leaks it’s a good start ! 👍
Decided to go the fusion 360 route. As CAD not my thing it's somewhat overwhelming . Not sure where to start. Need to find some example videos to create 'simple' shapes.
I personally would not use any silicone on the trap . It should work “ as is “ . Also if it needs to be removed later it will be far easier . Pipe off trap is just hand tighten yes - no glue .
I’d say tile adhesive as it gives you more ‘play’ . A sand /cement mix will depend on your mix .
I think it’s one of those things where either method would work tbh . Understand you want to be confident before you commit !
What I meant in times gone by pb a shower enclosure and then simply tiling over it . Slightest of grout failure and the pb soaks up the water and the wall becomes unstable .
You know what happens . Initially you see you can get something for around 200 . Then you look and watch videos / read reviews and see more toys for more £££££.