Sure Chad, I just edited my post above to add: drag chains can leave some crust prone soils too smooth behind the planter, increasing the chances of crusting and difficult emergence.  Sure, in some soils it may not but in many soils too smooth a surface will crust.

Doing a good job of clearing residue up front with row cleaners to eliminate residue in the seed slot and help maintain uniform seed depth, then getting good seed to soil contact and breaking up sidewall compaction with Curvetines, leaving the pockmarks as pictured in Joe's 2 per row video above will almost completely eliminate crusting problems.

Using a drag chain to smooth the soil surface negates the benefits of the pockmarks and puts us back to a crusting situation in many planting and soil conditions.

Some closing wheel brands require drag chains to pull soil back in that has been tossed up. Curvetines do not require drag chains nor a seed firmer to hold the seed at the bottom of the slot.

BTW the plastic flap in my photo above is used by this customer to prevent seed bouncing because he plants beans at fairly high forward speed to cover ground with a 6 row setup. Speed is often more economical than width, especially in the numerous smaller hillside strip fields many folks plant around here.

Jim at Dawn