I had a tough time with this mid-air refueling stuff. Spent two solid days and got nutin' but a sore shoulder (but my stick is a lot smoother at center, now). Figured the problem was in the response curves for the Warthog and came up with these... I could not hold a position with the tanker until I put in the stick curves.
But what really took the time was the throttle - I tested over 20 throttle curves and settled on the second pic, below.
This is simple curve I use for the stick - it was fine after a few tries, using the same on both Pitch and Throttle -
This is the Throttle - I had a heck of a time maintaining speed with the tanker, and this is what I settled on - *let me know if I'm missing anything* :-)
I made a misson with a KC-135 at Angels 15 on an 80 mile leg out and kept going over it, and over it... (All weps Off, but still managed to send a few tankers down in flames.)
I also Pause my TrackIR for these refueling ops. Too much forward-backward throttle issues w/o the visuals doing the same.
Hope this helps - you should be able to zoom right up to a tanker and hold position to it now :-)