Mike, I don't quite know how I came by my method, but I believe it is the 'standard' approach (whatever that means). At any rate, as I go around the 360 degrees of roll, I am blending rudder with elevator almost constantly, but not too much of either, depending on the airspeed of the model (more airspeed requires less control/correction inputs). So for instance at the 1/8 position (rolling right) I have left rudder increasing and pull elevator decreasing; at 1/4 I have left rudder maximum input (not full stick, but I stop adding rudder at 1/4 and past 1/4 start decreasing it); at 3/8 I have left rudder decreasing and push elevator increasing; at 1/2 I have rudder passing through neutral into right rudder and push elevator at maximum (again, not full stick), and so on around the clock.

Now I can't say my inputs are right on the money at these points of the roll, but they are definitely simultaneous inputs, and definitely one increasing while the other is decreasing. If it's a strong breeze across the flight path, don't ask me to explain how to wind-correct at the same time, but it's 'more of the same'.

I think I was persuaded into this approach some time back by talking with a very accomplished pilot who flies what I believe is Mode 3, with rudder and elevator on the right stick. He explained that for slow rolls,rolling circles and rolling harriers his right stick input is pretty much a stirring motion, with the stick going around in a circle or oval path (which of course means elevator is increasing as rudder is decreasing and vice versa).

When you are set up with elevator & ailerons on right stick and rudder on left stick (as I am), the coordination is something akin to patting your head and rubbing your belly simultaneously. It can be learned, but it doesn't come naturally to most folks.

I will say in all modestly I am capable of turning out a pretty straight slow roll. Sometimes, anyway.

I should also say I normally trim for slight pull on the elevator for straight & level flight. Not much, but a little, which I try to balance against the push needed to keep straight & level inverted. Where you have your CG is also a consideration in this set-up. I'm typically between 30-33% of MAC for my aerobats.