Nice trailer, I almost bought the same one, non hybrid version.
I like your suspension upgrade, well thought out and on a tight budget.
I'm more a fan of units built on a budget than units bought/built with an open cheque book.
Glad to see it is working and you are using it too.
But I agree with the other comments, always build beyond the minimum. The minimum is speced for pavement.
My trailers are 2000# capacity but both were bought new with 3500# idler axles and 15" tires.