Cannot reccommend these enough...
I have an 8x4... reason for going the larger length is because I got the secured wheel locks which only work on the 8x4...
The secured wheel locks are awesome... u just roll your bike up on the trailer, and as soon as they roll into the wheel lock, the bike stands upright by itself so you can take your time at securing the bike properly... totally worth the money... I got 2 of them for when i need to transfer 2 bikes, and a standard wheel channel for on the occasion I need to transfer 3 dirties when I acually get one...
Also got the box kit which puts walls on the trailer in case i need to transfer shit...
All up, was a bit of $1000, but for what i got, the ability to use the trailer for diff occasions, and the fact that its folded and hiding behing my house in a corner for the last 9-12 months unnoticed is worth every penny...
This will stay with me till i die...
When i was at the island one day, I did notice that some dude had one, and he had put some sort of rails underneath the wood for all the screw points, so instead of the bolts screwing into the wood, it would screw into this rail... clever idea, and I will definitely look into it when i have the time...