A good emperical test to be sure, but . . .

You're comparing a .46 two-stroke that costs twice what it's peers do with a .70 four-stroke that costs half what it's peers do. Compare the .46 AX with a FS 70 Surpass II. Or even better, a Super Tigre .51 vs. an OS FS 52. Both are ringed pistons and of pretty similar diaplacement. The OS actually weighs 3 oz less, but you're certainly not going to have the top end of the Super Tigre. The choice would depend on the model. A Pete n Poke or a 1/6th scale J-3 Cub vs. a Dazzler 40 or an Ultra Sport 40. Different engine needs in the same size aircraft (though I'd still have a ball with the .52 in the latter two planes - that's just me).