Christopher,
I use the 3027 drum with the plastic insert for 11x14. It works very well. Unfortunately, the inserts are no longer made. There have been one for two for sale on ebay over the past couple of years, but they went for a lot of money. When I get some time, I'm going to fabircate another one just as a backup. The trick will be duplicating the hold-down tabs so that I don't end up with uneven development. That is not a problem, in my experience, with the Jobo supplied insert. I've tray processed 11x14 in the past, but prefer not to do that.
Allen
Allen