Matt,
You could stack a 3x barlow and get it to f/24. That works well from the results of those that do it in our club. But a one shot web cam is the best way to go. My filters all come to the same focus. I'd be dead in the water if they didn't.

I almost had too much light here. Checked the full header and the exposure was 0.001" which is the shortest I can do and the ADU count almost hit the non linear part of its range. The only way I can image the moon is through the Ha filter! Otherwise it saturates the CCD. I had a web cam but one of the grand kids pulled it off the shelf. I didn't see it and stepped on it. Now I need a new one! It was only USB1.1 so too slow and a lot fewer pixels than those of today so no real loss.

Rick