This fall we baled some grassy corn stalks, using a rented BR780 baler without netwrap while the fire damage on ours was being repaired.   I hope I'm remembering what my brother reported correctly...I think it was 43 seconds to fill and 32 to twine.  We baled some years ago with our net 664 in a year where favorable weather really brought the fall panicum on after harvest....according to what I timed then he was filling in about 35 seconds and wrapping in 12.   Talk about chucking out the bales. 

When there is panicum to be had, we run the disk mower and then v rake.  If it is just clean stalks I think you will get better feed by just raking it because you get mostly leaves and husks.  OTOH, back in the year we baled a whole lot of stuff after harvest we tested everything and there really wasn't any difference in  feed value between corn stalks mowed or just raked or letting the panicum grow up, but that made a lot more hay  Actually  all of it tested better then the prairie we baled that year.  This year it never rained and the panicum never did much.