Built in over flows have always had issues for me.
I prefer the hang on type, or I suppose you can build a hang on style permanently affixed. If you can modify to do a bean animal design with the built in(tough to get that many bulk heads in the small space in most of them), likely will be pretty good then.
I add CO2 near the suction side of the return pump, some tanks I sent the water to a reactor and then the outflow to the return pump, feeding the CO2 into a needle wheel powerhead that sends the CO2 froth to the reactor.
This removes most of the mist.
The pearling seems to enhance clarity, so good plant growth= better clarity. Even with the mist.......larger tanks, the mist can become an issue for clarity.
But a post reactor will solve that issue and improve CO2 use efficiency.
Still, CO2 usage, maybe only 1% at best actually goes to the plant, the rest is degassed.
Regardless of the method used to add CO2.
I use foam blocks only really.
The Bio bale (CPR stuff) and some bioballs are all I'll use.
Foam is from swisstropicals.com 20 ppi.
30 ppi clogs too much, I'll use 10 ppi on prefilters, sometimes 20 ppi.
If you demand more clarity, then using say a Nu Clear or OC canister filter on an independent loop(so when it clogs, the main filter flow does not drop) would be a wise thing. Water change flow up into/out of the main tank, or you can run it in/out of the sump.
These run at 20 microns, and clog after 1-2 weeks for many planted tanks in the 120-200 gallon ranges.
A semi clogged foam block is a VERY good filter for clarity though.
Very clogged= bad or newly clean= bad.