Jaka,
Thanks for your input on the subject here. My fuel tank is mounted as low as it can be without modifying or cutting into the cowl, it has been lowered from stock when building it, the engine mounted at 8 O'clock cylinder position has lowered the carb on this model. plug is OS 8, prop recomended as per OS is an APC 13x8, fuel is Omega 10 to 15%.

I am thinking most of my problem is the way the engine is mounted, seems when the cylinder is pointed downward the idle mixtures need to be leaner to help prevent it from loading up.

Yesterday the slightly larger fuel line helped some, today when I flew I used Omega 10% rather than the 15%. The engine ran great today. Im sure that the small changes in nitro and fuel line didnt do much but it was enough to clear up the midrange symptom. Im sure that the heart of the problem is still there and finding that, may give me better power in the midrange.
It was convenient to install the fuel filler with the cowled set up but I will try the 3 line method as you mentioned. I have done that with my Sportster and it works fine, you're right about eliminating all that unnecesary stuff, sometimes it just causes more problems.