That looks like a nice job and plenty beefy for bikes or a light trailer.
I had a professional shop do pretty much the same thing on the back of my enclosed car hauler so that I could haul my 300lb scooter on the back of the trailer.
I too was concerned about having enough tongue weight, so I bought a tongue scale($45). Hanging the 300lb scooter on the back only took 75lbs off of the tongue weight.
Of course, depending on placement of your axles and how you load your trailer will determine the effect on your tongue weight. I would recommend a tongue scale to make sure you have enough weight on the front.
