That will only work in Vegas style machines.

The machines from Japan will most likely have to have a plastic cable tie placed (glued down) in the travel area .. where the coin rolls through the comparitor. Basically you are trying to tell the machine that a quarter is the same size as a 0.984" token by raising the coin up.

You are probably better off in the long run playing with tokens in the machines from Japan since you risk damaging the hopper.