Tuners make perfect sense on 22rf's, because you need to tune the rifle to the ammunition. They also make sense on a factory rifle shooting factory ammo, because you gotta tune whatcha got to what you're feeding it.
But, I'll cast another vote that a custom rifle with handloads shouldn't need a tuner. There is something askew with your bedding, stock, or perhaps the way the barrel was fit to the action. Something is causing a bad vibration that is opening up your groups. The donut is the quick fix.
My greatest concern with a donut on a hunting rifle isn't that aesthetics, it's that the darn thing could get knocked out of position, or knocked off and really mess up my POI.
