If I add raised wingtips to one of my RC planes they significantly decrease the aileron authority, meanwhile improving the dihedral effect and the self-stabilizing tendency. But for maneuvrabilitymaneuverability, it's not as good. If I add an autopilot, like Ardupilot, the raised wingtips will make harder for the autopilot to instantly correct the levellingleveling when passing throughtthrough turbulence, because the effect of the ailerons is dampened by the self-levellingleveling tendency. Basically, the ailerons have to fight not only to change the attitude of the wing, but against it's tendency to rotate by itself, that might not act in the right direction when flying through turbulent air.
If I add dropped wingtips, they improve lift (the same wing is capable to carry more weight) and they increase greatly aileron authority, while decreasing passive auto-levellingleveling.
The plane becomes harder to fly manually, but for the autopilot the effect is good, because the smallest deflection of the ailerons will have a big effect. The autopilot is capable to correct instantly the horizontal attitude of the wing, by moving the ailerons very fast, and in minute increments. The plane will look like it's flying on rails, even when it passes through turbulence. And the lower the altitude, the greater the turbulencesturbulence, because the wind is moving over ground obstacles and it's not flowing laminarylaminarly. When the wind is strong and there are bushes and trees on the terrain, the turbulencesturbulence can be so great, that a RC model can become impossible to fly low if it doesn't have some sort of electronic self-levellingleveling device.
The conclusion is that, for a plane that has to fly low, dropped wingtips and an active self-levellingleveling device are the best combination. If the plane was low wing - high CG, I would have used raised wingtips.