Then I guess I'm having trouble visualizing it. When you say sagging I am picturing the mains being more squat than they should be. If that is what you meant then flying a high angle of attack like you would have in a flare would keep the nose wheel high and off the ground. It would be possible to land with no mains at all and only a nose wheel and not bounce.

If you meant that the mains are sagging such that they are lower than the nose wheel then they would touch down first any way. The point is that proper elevator/throttle control can and will keep the nose high. If the nose is coming down first then it is either way to fast or way to steep. (flaps would allow steep and slow) in either case slow down and pick the nose up. it will land bounce free. 17 yrs flying RC and a handfull of hours in full scale just tells me that if the nose hits first its because of pilot error. too fast and not sagging gear whether the gear is sagging convex or concave the nose must be kept up.