From what I read from the experts in various magazines, the trailer tongue should be 1 1/2 the width of the axle to be towed without any issues. From your pictures it shows that the tongue is at least 2 times the lenght of your axle. The trailer will sit way too far back from your bike. Perhaps you should check that out. Just a suggestion.
I built a HF trailer as well and made my tounge nice and lont (space for cooler rack later!). Longer is ok... Just dont get too short. mine is a littel more than 2x the axle, and worked great, has about 1000 mi. on it now!
The longer the tounge, the less tounge weight you have (important if you put a 35 qt. cooler full of ice on it!), you just have to make sure that the tounge doestn't get too light, It will track funny!