I have a 6x12 and with my ultra in it - no way you're getting another bike in. Even in my mini barn, the opening is 47", I only have about 2" - 3"'s on each side to drive in. A 7x14 is the way to go, stagger the chocks and it'll be fine.
Sorry...typo. Mine is a 7x12. I can do 2 baggers, but yes it is tight. Placement is key with the chocks thats all, and the v-nose is what makes it do-able.
Don't think 6' is wide enough. I have a open 5x10 trailer and I tried to fit two SG's on it without success. I don't think an extra foot of width would have worked either. Another thing to consider is with an enlosed trailer nothing can hang over the side to help conserve space.
I have an open two axle 8x12 and hauled staggered my wide glide with bags along with a softtail custom with bags all the way to sturgis and back. I know I can put two full dressers in staggered. My only prblem was driving the wideglide up thedrop down steel mesh deck and snagging some metal. Wideglide is lower than the softail custom. My ultra can go up the ramp with no trouble.
I have a 6 x 12 V-nose single axle rated for 2990lbs. I can get a Fatboy and a Dyna in it. Hoping a RKC and a Fatboy will fit as well. But, I can't imagine fitting two bikes with hard bags and fairings in it.