Is this mostly an issue when you are traveling mobile (like in a car), if so I dont have good news.
I have a uniden bc296d and a GRE PSR-500.
No matter what I do, I can have issues with digital cut-off on either scanner when monitoring 800 MHz digital conversations.
I tried an 800 MHz specific antenna, but then it would bring in weak sites (when monitoring multi-site systems - like OH MARCS) and then the cut-off would be even worse. It was better using the stock rubber duck, then the weak farwaway site (that I wasnt interested in) wouldnt even be picked up.
The good news is sometimes when I get digital cut-off, I hear a dispatcher say 'repeat, you broke up'....so Im not the only one.
I personally prefer analog radio. That way you can hear through the static vs. a straight cut-off.
As for settings, maybe someone can help. I have issues on my PSR-500 where no-matter how high I raise its 'low' threshold setting, it will still bring in weak sites when a better site is available.