It's not about the weight of the trailer, it's the tongue weight. When you attach a SW or DW to the 5'er the cart puts weight on the back therefore making the tongue come up. I'm kinda thinking a DW may not lift it as much.
My Cougar is already a toy hauler but I have a problem getting the cart in with the big tires. The back room is rated for 1k pounds so I doubt I will have a problem. One thing I suggest if you're going to do this, is go on Ebay and buy a tire pressure monitoring system. I found a good system so if you're interested I can give you the link. You don't want to be towing this thing and have a flat and not know it.
When Lonestar and I publish our book "How to spend thousands to get your cart to the fort" we'll send you a copy lol.