frame doubling in Twixtor

I have some 12.599 fps video shot on my old digital camera that is way too choppy to view. I'd like to double the frame rate.

I'm experimenting with Twixtor in AfterEffects with some success... but not sure it's doing what I want. If I just want to interpolate intermediate frames to double the framerate up to 25.198fps, then I shouldn't be seeing pulsing every second or so. It's NOT there in the original file.

So does anyone have any experience with Twixtor and know what settings I should use for simple frame doubling? Also... how to save files with audio.

Thanks!