Tabbing down will do it. What kind of tabs are you running? K planes will work best with probably least amount of speed scrub. A labbed prop will generally increase your RPM, not drop it, since the blades are thinner. Labbed props will have a thinner, sharper edge. If your 27s are labbed it would help explain how you can still keep your RPM up.

I have K planes and I only need to tab in rough water, in smooth it doesn't walk as bad. I've learned to "steer it" when it starts.

These are just regular Mirage props, not Mirage Plus if that makes a difference.