Scooterotica

Hi all,
building a 71mm Monza barrel with Wiseco piston on a 57mm crank with 116 rod.
Head has been modified with a recess 2mm in the barrel.
TAssembling with a 4mm + 1mm (couldn't find a 5mm one anywhere) base gasket and squish measures out at 1mm.
Allways read and been told to keep it in between 1,2 and 1,5mm.
Exhaust is ADS3 low revving torque expansion.
Do I risk the 1mm squish or do I need to go looking for a 1,5mm base gasket instead of the 1mm to add to the 4mm one?

I'm running a RT225 with a 1mm squish been ok so far but hey if it was 1.5 it would probably still break, after all it's a lambretta.