While this is a small edf, without knowing these systems well you've jumped into the deep end! First, do you have a watt meter to see how much power the system is actually pulling? Second, that sounds like a very high kv motor which might need special timing settings in the esc to run right.
As for the lower power on your second test. That esc is really close to its limits. There's a possibility is affecting things. You may need to 'teach' the esc the tx's throttle range. Does the esc instructions cover that?
Lastly, intake and exhaust ducting play a big part in edf thrust. Especially an exhaust tube. The exit should be 80-85% of fan swept area. (FSA) That's the area of the edf that air actually passes through, total fan area - motor area = FSA.
Mind you, I'm no expert at this. Most of this is what I picked up reading through forums. I have some 64 mm and a 70 mm edf's, 2 of which I've upgraded. I think it's harder to set up an edf than a prop. But I think the above items are all possibilities. Hope something will help.