[Imp]

Blocks would not work, in your example why cant the 199 engage the 200.
Agree with the idea though if its codeable allowing units to CBF on units whose range is less than say 20 higher would solve the issue.
At the moment if you have the range advantage you know your units are 100% safe, about the only thing in the game with no randomness.
Also means smaller calibre could occasionaly CBF the big boys with the longer range.

If desired could make it another option on the artillery supply screen.
Reserved for CBF gets to engage as above for a penalty to on map call times.
Or just let batteries bought as general support CBF units with a range 15-20 higher, think they already are more likely to CBF than other units