I do like above but I just close the clevis and make me a little tool out of lite ply or whatever I have that will fit between there to turn it.

Also I've had some clevis's that the back part that's hex shaped is the same size as a bicycle spoke and you can use a bicycle spoke tool. I'm not sure on the avistar even tho I have one. With the spoke tool it's the easiest thing to do cause it's slotted to allow it to slip over the spoke and turn it by griping 3/4 of the way around it.