First off I say "Good for you" for taking the time to do it yourself and understand how it works. When you are on the road and something happens it is good to know your entire setup.
One thing, and I made this error initially, is that you said you measured the hitch height. Did you measure the trailer frame front and back? If so did you measure the hitch frame in front as it is lower to the ground than the actual trailer frame? It does look front high. Can you drop the hitch head down a hole on the shank? I can tell from pic if there is room for that. That would bring the trailer front down and you could then readjust. Aside from that it looks and sounds like you are doing the right thing to get it adjusted properly. The general rule is to get the front within a half inch or so of unloaded, have the trailer either level or slightly nose down. The rest is truly about the balance of weight. With measurements you are just going to get it close but once close a trip to the scale can really help you dial it in. I think you are well on your way.
