I had much the same peoblem with mine, except mine involved a garage door! Before I start the next bit - how do you posityion the engine when youy store it? If Up, there's a good 9" to be saved just by dropping it. If dropped, are you on the bottom hole (manual engine maybe more likely to suffer from this as PT usually has the pin in the lowest hole anyway)- you;d be amazed how much space you can savve by doing that. also swing he engine hard to port or starboard.
If that doesn't work, - pretty much what Bam Bam asid - rebuild the trailer. I had to do that with mine - was made a lot easier by having a friend with a tractor / back actor & a set of slings , which meant I cluild lift of & on, because the only other option is launch & recover 28 times.......
One way to approach it -
1) work out how much length you need to loose.
2) will the winch post move that distance forward?
3) if yes, launch, move winch post, also move rear swing beam forward by the same amount. (that distance isn't going to change)
4) Move the axle forward about 2/3 the distance you moved the post. Unffortunately this is only a guess, and from here on, you just have to recover & launch it, shifting the axle slightly each time until it's balanced again.
When everything is in the right place, replace all the nylock nuts with new ones.
PS if it's a swing beam roller you may find you don't need the drawbar extension. Having said that, I've no idea where you launch.......