It can be done, I have a wells fargo trailer with the same dimensions. Only one of my sleds has reverse. What I do is load one sled from the front and drive it to the rear, then put the back end as far over to the wall as possible. Then I drive two in from the rear, the first one goes in and then is slid over against the first one, the second one is driven straight in and again the back of the sled is slid against the wall. The fourth sled is then backed in with the back of the sled fitting in between the others. With this pattern the backs of the sled are all overlapping each other and since that is the narrowest part of the sled will all fit.
As was said earlier will depend on the track lengths, normally I have a 153, 144, and two 136's with lots of room left over but I have carried the 153, and 3 144's and still had room left over so I know I could get longer ones in, just no place left to walk, you crawl over the sleds.
Nice part is with the shorter trailer parking, turning, etc is not as much of a hassle.