In a TV set is the blinking evident?
On an old CRT (cathode ray tube) monitor, yes it is very evident and will look horrible. Especially in PAL (50 Hz) regions. I have never tested a 60 Hz CRT, but it is probably a bit less worse, but still bad. Someone from america or japan could confirm this.
However on modern flat-screen TVs, what BMF54123 said will happen : The lines will alternate, looking like smaller pixels. It's a bit hard to explain unless you see it.
A good example for this is the airship's shadow in Final Fantasy games which flickers at 60 Hz. On my new screen, it looked like the shadow was solid, but with horizontal lines half-a-pixel height. Also they would slowly alternate between the upper and lower half of the pixel, making it look even worse. I have no logical explanation for why it is like this, it just happens to be like this.
My vote would be for dwedit's solution, it really looks almost as good as a true two-layer sprite, and is only one sprite more horizontally, for a total of 3 sprites, instead of being a total of 4 sprites, which makes a huge difference in reagard to the 8-sprite per line limitation.
Also, Diskover, I should congratulate you for handling sprites the correct way. Usually, newcomers tries to use the value inside the OAM as being used like variables for the sprite's position, which is terrible practice.