Once you get all of the crop residue out and you're ready to disassemble the cylinder, slide a big piece of cardboard on top of the concave to catch all of the bolts, nuts, wrenches and whatever else you will undoubtedly drop in the process.  If you have to use multiple extensions on your ratchet or impact to reach a bolt, tape them together, and tape the socket to the extension.  I've used these tricks when changing cylinder bars and it saves a lot of aggravation.  It seems to me that you've had your share of that already.  Depending on how long you plan to keep the machine, this would be an ideal time to put in new bearings, but they will be pricey.  At least make sure the old ones actually take grease instead of bypassing it like they often do.