I know this is over a month old thread but I found it through a search and I figured I'd throw my two cents in.

Around here the big guys are taking 1770 and 1770NT 16 row front fold planters and pulling a John Deere 19x0 air cart behind them. I know one guy with a 1770NT CCS 16 row 30 and the air cart who is pulling it with a 9220 that has a 48 gpm pump and says he has problems with being on the edge with hydraulic capacity. I know another guy who has the same setup except he's pulling it with a New Holland TRJ 325 with a 55 gpm pump and has no problems in terms of hydraulic capacity, so it looks like having a little over 50 GPM with this setup would be the way to go.

For openers they use the John Deere single disk openers. You can get the old style for dry straight from John Deere but if you want to use the new style John Deere single disk openers you have to modify the boot on your own to make it work.