Just found this thread.. am a little behind on few sportster building thread I didn't know until tonight..
I see that you are done with the fuel tank there? Nice work! I am still contemplating on what I want to do about my fuel tank. Most likely going to build my own fuel tank but think I am gonna try to build a 6-7 gallons tank using 5052 H32 1/4" aluminum plate (think I can drop down from 1/4" to .90" but still researching). The reason I am going with that aluminum is because it came highly recommended by both hot rodders and airplane builders as it has no chemical react and is strong enough. I know some use 3003 (if I have # correct) but I just thought that I would share that info in case you might want to consider it for your Aux tank project. Also any idea how many gallons on your fuel tank?
And interesting choice of fairing/dashboard.
I'll follow your thread from now on to see what progress you have done as you go along.