If you always think and act in MM then it would be more fun to have a dial indicator with a MM face on it....they do make them...

Although it is not available the FIRST time you do it... saving the OLD race and grinding about .001 off the edge will make a great removal tool for the next time... I always save old races ... then weld a suitable handle to it... very fast and easy from then on... but the chisel should work fine the first time... just go evenly around the edge.... well... I mean skip around the edge in about three places with small hits to drive it out as straight as possible... getting it cranked sideways really increases the pressure needed to get it out...so slow and even it the key...

When you do get it out... I wonder if there would be anything wrong with using a small grinder and making indents for the future... they are nice to have....