you shouldn't need a huge amount of throw in the NEXTAR aileron as it is it will do basic maneuvers with the throws out of the box if its the RTF version.
if you have the ARF then screw the connector on the torsion rods down about a 1/4" from the top and use a large cross horn with the push rods connected on the outer most hole there should be enough throw for most needs.
something to check is how tight are the torsion rod connections into the aileron is there any slop or play, they are not glued in as I can see just pushed into a hole in the aileron, after just a few flights mine became dangerously loose and floppy and I had to cut the wood back away from the wire and filled the channel in the aileron with 6 min. epoxy, after that they have been solid ever since.