@jrhooker
You could try using NDI out of Isadora into NDI in Watchout. I've played around with that and it works, though never used it for a show, so you would need to test how stable it is... But that is maybe one method to run "through" Watchout.
I've been frustrated a few times with venues insisting on using their (often antiquated) Watchout systems. If trying to use Isadora completely instead of Watchout the thing to avoid is trying to use their Watchout computers to run Isadora. Watchout usually requires a whole list of tweaks to the BIOS and other parts of the computer to function most effectively, you kind of have to undo a lot of those tweaks to make Isadora run well (its quite tedious and annoying). It is better to leave the Watchout computers alone and see if you can bring in an Isadora show computer. Watchout uses a server-client mentality and thus often people will place the display computers local to the projectors (or other displays) and having the production computer in the booth or show position. Isadora is usually more centralized with the displays being run directly from the show computer. If it were possible to run new lines to the displays (Active Optical HDMI cables, would be ideal for the cost and convenience) and leave the rest of the Watchout infrastructure untouched - only replacing the input to the projectors, perhaps they would be amenable to the idea?
Hope that helps? Best of Luck.
Cheers,
Cam.