When using the KO system, what would the IRC and the Key Count be
for a 4-deck game? Should I approach the game the same way as a
6-deck shoe or 2-deck game?
The standard IRC is -12, but of course you can choose whatever IRC you find convenient.
In any case, key count is IRC+11, and pivot point is IRC+16.
Take insurance at +15, and play the four deck shoe the same as six or eight.