Modding (or not) a webcam for astro imaging

[Probablynot]

I read with fascination (and admiration and gratitude) the SGL thread http://stargazerslounge.com/diy-astronomer/96400-hd-webcam-modification.html about modding a webcam for astro use.

I bought one of the webcams it mentions. I have no optics/electronics qualifications, but I'm confident I can follow the modding instructions. I've got a suitable eyepiece I can sacrifice for the job, and the UV filter's on order. So what's holding me up?

Two things.

First, it's a such a good little camera without the modding. And if I hold it up to my scope with an ordinary eyepiece fitted, it will take pictures. Not superb pictures, I know, but that might change if I were to tape it firmly to the eyepiece.

Second, I'm having difficulty understanding the logic of using the webcam, stripped of its original lens (I've got that right, haven't I?), and without fitting an actual eyepiece to the telescope. Or does a Barlow have to serve as the 'eyepiece' when using a webcam?

Before I start attacking the webcam with my set of miniature screwdrivers, will some kind expert please explain how the light from my primary mirror, via the secondary mirror, provokes the CMOS chip into producing a nice, sharp image on my computer screen?

And would a 3x Barlow be any better for the job than a 2x?