Hi Gostbear,
screwing the control rods down closer to the control surface is an invitation to flutter, moving the rods farther out on the servo arms is a better method,up and down is controlled by elevator ,not ailerons and if the plane is nose heavy there will not be enough elevator control while inverted,some people crank up the ailerons so the roll is fast,trying to hide the wollering
effect,practice slow rolls as if the plane is following a stright line,or flying on the string.
Have a goodun,John