I truly understand what you are asking. But since virtual magnification is distorting the pictures (pixelation); we don't really focus on magnifications. So, no, our ZoomEffect extension doesn't support setting a default magnification level. It starts with x1 and goes up as you scroll the wheel. By the way; i would recommend you not to use the magnification at all for a better UX.
Ideally; you should upload minimum of 900x900 resolution pictures and set thumbnail size around 300x300, so the zooming will be X3 without distorting or pixelating the pictures (or upload 1200x1200 pictures if your product page is suitable for 400x400 thumbnails. Keep the zooming level somewhere between X2 and X3 -- without magnification) -- the UX will be much better and your store will look more professional in that way.