Well, camtasia does not output live,it’s a recorder, so if you are wanting a shot of the two people on the set with the laptop output blown up on a monitor alongside them, you’d have to fake that in post. That adds time to the project. If you could record live, you’d save a lot of time.
The way to do it live that works for me is a quality scan converter attached to the laptop: this works in real time, so you can take the scan converter output thrua D/A and IMAG it to the on-set monitor as well as time it and feed it into a switcher as if it were it’s own camera shot. That would look really slick, and save hours in the edit.
Yes, you could do this same thing with the direct s-out of the laptop if it has that, but the converter lets you scale and proportion the image to fit TV safe title area, and reduce flicker, as well as blow the image up to high maginification for some of the really tiny details you want to show clearly.
I always personally endorse the scan-do line from Communications Specialties, having used them a lot, but there are plenty of other brands out there that can work as well. The good ones are several grand, so for a one-time or infrequent user, you’d want to look at renting it instead of a purchase.