I bought a 404 recently and an operator's manual. The manual says that you need to get back on the cuttings within about 10 minutes to get it crushed before it wilts. Assume they were referring to Alfalfa. The stuff we grow down here for cow hay wouldn't care if you waited till the next day.
Apparently the wilting causes the crop to be too supple and not stick to, but follow the rollers around and eventually clog up.
On what to use, I have used straight sickle bars where crimping wasn't required and MOCO's of the green and red (NH) colors. The MOCO is an excellent choice if you have a larger operation with rectangular dimensions preferred. If you get the JD, ensure that you get the tongue extension (same one used with the round balers works) also so that you can make 90 degree turns at the end of the row with minimum missed crop. The JD 1209's were my favorite; had 2. Wobble box condition important and the bolt that holds the sickle has to be torqued as stated: 150 FT-LBS.
Currently I am running a much smaller hay patch and am tired of sickle bars. Reasons are crawdad mounds and aunt hills clogging them and repairs, especially if you need to pull the sickle bar are a real pain for me. The MOCO is more than I need or want at 9'.
I bought a 6' drum mower last spring and really like it for my little place but want to plant crops that are stemmy. I found a 404 (which crimps a 6' row also) and later a locally made similar unit and will use one of them this year on my hay patch.
Yes I will need to make an additional pass that wouldn't be required with a MOCO but for me, in my present operation, that's ok fine.