tank171, Welcome to MTF! I did not see where a flail mower was available for the 2305. I would check with your dealer to see if a lighter duty flail mower would work. I have an implement brouchure at home and I will check to see but in the build your own section of the John Deere website, flail mowers are not listed as an attachment available for the 2305.:goodl:
I regularly use a 6ft flail with my NH TC30 (24 pto hp). The mower will completely stall my tractor if I try to go too fast and have let the grass get too high. In other words, you are not going to see me running 10mph thru near waist high grass like mower commercials show. On the other hand, if I slow up a bit, the cut looks great and no one can tell I didn't use a 50hp tractor.
There are smaller flail mowers made that could work like that for your 18 pto hp machine. Here is a pic of a 48" one I found on Ebay. There are other sizes available. If you don't have to run at high ground speeds in a big hurry, a flail could work just fine.