between these two mid-range consumer camcorders is that one has a "projector" built-in for playback in a dark room (so no TV or monitor is required).

Assuming your version of Pinnacle Studio, computer hardware (RAM, CPU, available hard disc drive space) and operating system can deal with AVCHD-compressed video, then you should be fine.

Don't worry about "digital zoom". It is useless and should be disabled in the camcorder's menu when you get the camcorder out of the box - assuming you want best available video quality. At very worst, you can use about 10%-15% digital zoom beyond the useful optical zoom - but you can do that with your video editor, so disabling digital zoom in the camcorder is generally easiest. Yes, optical zoom is better than digital zoom.

Both the HDR-CX260 and PJ260 have 30x optical zoom. When zoomed in on something, be sure the camcorder is mounted to some sort of steadying device - tripods are most common. The floor, table, chair, rock... anything... will better than handheld.