Most provide 2 or 3 choices on length of cut, and you must keep the knives sharp. Some choppers can be inserted after the bale begins, and removed at the end. Chopping can add to the density of the bale. May be a plus in some feeding methods. Use plastic or untreated sisal twine.
Regular sisal has an oil-based preservative that can damage the film.
Inoculants can help guarantee good fermentation by providing lactic acid producing bacteria and enzymes. Best to transport bales to storage area before wrapping. Have storage area prepared and clean of sharp objects like rocks, coarse stubble, and sticks. Also eliminate nesting areas for rodents. Plastic always use quality film with 1 year warranty on the bale.