Twitch streams are usually the same thing you'd see in-game, plus you have a chatbox you can post questions to so the GM can not see them because he's not watching the stream. :P The advantage of watching a stream for the GM is there's one less player in the game to accidentally move a bunch of stuff around or hit a button that makes something go wrong. Call of Cthulhu, hmm... AFAIK tactical combat is pretty limited as combat usually means you've done something wrong, and when it happens it's fairly abstract. You could use a map showing the layout of a town, or a house the investigators are creeping, or the ocean so your investigators can drive the boat into Cthulhu's head. Handouts and the die roller will be useful of course. I think the best way to get into it is to just think of what you want on the tabletop (whether it's a scary splash screen, a town map, a house map, or all of the above), import your artwork, create any dice macros/rollable tables you want, and approach it like a regular tabletop. After each session you might create some new "nice to have" macros and handouts, and just let things evolve from there. I run a GURPS campaign Monday nights. PM me if you want a twitch link (I don't really broadcast, just send to Twitch for backup recording when I remember to save the stream).
