HD Keying with Decklink Extreme HD

I'm interested in doing some live HD keying. In the longer term we're planning to develop our own software; however, we have a project coming up soon and need a solution quicker than we can do our own development. The decklink extreme HD appears to do HD keying and has some third party software support. Is this a good option?

My company does industrial inspection work and all we want to do is overlay time/date/location the whole time and then if we see an anomaly be able to draw an arrow to it add a label like "loose part". We then record this live video to give to the customers with a quick turnaround. It's impractical for us to save the video and then go back with an NLE and add the loose part designations in later.

I don't know much about this but it sounds like the standard way is to create the graphics in photoshop then import them to the keying program and fire them off. Is this pretty straightforward? Can we do that in real time? I've seen some third party software like the Datavideo CG-300 but it appears from the demo software that it takes awhile to create a new graphic before going live with it.

I'd really appreciate any suggestions.