ABU 7500C drag washer thickness.

[borntofish]

I was wondering if the drag washer thickness is critical - especially the under gear one? I replaced all the washers with carbontex on my ABU 7500C. I cut them myself from a 0.5 mm sheet. I have since found out that the under-gear washer is supposed to be 1 mm. Will it affect the meshing with the pinion gear or free spool operation? The reel seems to work alright, though what about wear in the long term?