Live chromakey setup

hi
I'm putting together gear for a live show and need some advice.
the show has two actors performing on separate green screens. Footage of them is composited live in touchdesigner, the result is played to the audience on a big screen.

We did a trial of the show, capturing the cameras with a Decklink card and pulling the key in touchdesigner. It all worked fine as a test-run, but it really needs better keying- I'm thinking of using two Ultimattes, like in the attached diagram.

The ultimatte outputs a fill and a key- I read that you can combine both into one 12G-SDI signal. Do I need extra gear to do this?

I'm trying to figure the best way to get all the cameras into the computer- would I be better off with a laptop and an Ultrastudio? A desktop with a Decklink card or two?
Would all that data travel over a thunderbolt cable if I go the laptop route?
Space and weight are considerations, too, because we'll be touring the show.
I'm leaning toward a small desktop with Deckink cards, but if folks have any advice, it'd be appreciated.
thanks

[Ron Ungerman]

Hi Doug
The Ultimatte 12 will output a Key and Fill and give you a far superior composite, but the Ultimatte 12 will not combine the Key and Fill.

How did you combine the Key and Fill in your test?

The show was put together in touchdesigner, we pulled a key off the greenscreen in there. It wasn't great but worked as a loose proof of concept.

So the way to go would be have enough inputs to bring in fill and key from both cameras, do the matte in touchdesigner?

[Ron Ungerman]

Yes,
But if the Touchdesigner does not do a true linear key, you won't be able to achieve a good quality key. The only advantage is that the Ultimatte 12 will eliminate all your green spill.
Is it possible to do the key inside of the Ultimatte?