Not actually, the drag due to the lift will, in 'S&L' flight always be about the same, no matter what the speed, cause lift will always equal the weight. This only changes at high AOA's and low speeds. The ratio of this lift drag to the rest of the airframe drag will change with speed, as you suggest, but the differences between the two, at model sizes, is probably not great. It is likely that lift drag is greater than airframe drag at low speeds, and the ratio gradually shifts to parasite drag as the speed increases. That's why, to go faster, you need to go lighter, in preference to cleaning up the airframe and increasing power, both of which tend to add weight. All things together, of course, will give the best results.
Evan, WB #12.