Question Regarding Installing New Shower Cubicle

[random bloke]

I'm shortly going to fit 10mm thick shower wall panels over the existing tiles and then a new shower cubicle onto the existing 1200 x 900 quadrant tray. I haven't yet bought the new cubicle but wonder if this additional 10mm will space the new cubicle out to the point it overhangs the curved section of the tray?

 

[polesapart]

Download the fitting instructions for your proposed new cubicle and compare the tolerances with what you will have after overboarding. Also, check your walls are plumb!