Hey Woo,

I'm not sure which solutions you have already attempted, but
one thing I have found very helpful for preventing overruns
with fluorocarbon is to not spool your reel too full.  Coupled
with properly set magnetics and/or spool tension, this should
all but eliminate backlashes and overruns.  

The KVD line conditioner is a good product. I would continue
to use it as needed.  I really like it for cold weather since
the line tends to have more memory.      

Just out of curiosity, which brand(s) of fluorocarbon are you
using?  I'm confident you will be able find a brand of
fluorocarbon and a system that will make you become very fond
of this line.  

Fluoro definitely handles differently than copolymer and
monofilament lines but in my opinion, the benefits of
fluorocarbon far outweigh any of its quirks.  I know it has
improved my fishing tremendously.     

Good luck!