I understand trying to make due with what you've got, but dragging a bat-wing mower is a job for a bigger tractor. The L3800 only delivers 30HP to the PTO so it isn't the right tool for the job. Are you looking to cut mowing time in half? Quarter? Less? An old racer saying applies equally here: Speed costs money. How fast do you want to go? Kubota makes some fine tractors that can handle bat wing mowers, but they require a thick wallet.
You didn't specify how many acres we're talking about or how often you're mowing it so it's hard to give a real accurate assement of your needs. Assuming we're talking about dozens of acres, You could pick up an older farm tractor in the 50-80 HP range for peanuts and use it for mowing. Save the L3800 for doing the smaller jobs that it's ideal for. Do I get banned for suggesting non-orange tractors?