here it is all sprayed up with everthing I needed to go out riding
ps. I just landed my first 360 unispin
Nice job man. Towing a trailer behind your bike gets half as much attention as riding a unicycle, but towing a trailer with a unicycle in it should get some looks!
+1 
look at this design, you’ll see it attaches to the back axle (or somethign around there, the dropouts maybe), not the seat post
Yeah, that’s the same as mine. You get a special quick release skewer with the trailer that replaces the one on the back of your bike. (I think you can get special nuts if you done’t have a QR axle). And the trailer hooks over it.
They look pretty good and from what i can tell, very durable.
I have towed BOB trailers, double wheeled trailers high hitched trailers (similar to the one you built but with the wheel behind instead of under) and used a cargo bike. The cargo bike rules but of the trailers I have used the BOB was definitely the best. If you ever consider building another trailer you should consider using a design similar to the BOB.
edit: you can get the skewers and the front fork separate from the trailer from BOB and build the rest.
…and it’s got suspention! Prob good for those long trails leading up to a good trials spot.