I too would vote for the double axle trailer. I have a 14x6 that when I place my BX25 on - two things have to happen - curl the bucket so it stays inside the frame of the trailer, and swing the hoe to one side, doing all of this gets the centerline of the tractor forward of the centerline of the two axles.
If I had the $$$$$$ I too would get the 16' trailer, most of those at a minimum have 7000 lb capacities. you machine and all it's parts will get up there close to 3500 lbs depending on what cha got on it at the time.
when the man dropped my BX off two years ago, it came off a SINGLE axle trailer, a 12' wide and when he backed off the trailer , the trucks rear wheels left the ground slightly!!!
a tilt bed is super nice - but sometimes the budget gets in the way, IF you buy a used one, it will rarely go down too much more in price in the future, i.e. - you buy a used 6x16 dual axle for $2500, if you take care of it, it will be worth that 5 years from now.
post pictures when you can!