It's not a Neos (which mounts ahead of the axle) .. just a standard off the shelf rear derailleur.. lots of options .. not so much with the Neos .. and I wouldn't exceed the actual derailleur capacity.. there will be times you just forget what gears you are in and you will bind it up.. this stuff is all pretty obvious once you have it on a bike stand to quickly see what works and what doesn't .. a good shop should breeze through this..

Check the specs of the Vector P20 11/36 in rear 53/39 and a mid cage derailleur.. you should be able to do something quite similar with the Formula..