My FP has 20c and 50c mechs where I just filed the original slot plates to suit the coin sizes,
I bought some aussie mechs off fleabay,the 50c turned out to be a 20c so it got the file treatment too works well on 50s now!
even got it to reject 20c and smaller,1credit 20c and 3 credits for 50c
the plastics I used come with the CPR Plastics set could prob stencil the denominations on them.
Peter