Help with LIV and OBS with alpha foreground

[Fdruid]

Hi, I'm dabbling in using LIV and OBS to record mixed reality videos. I got the basics working, it's all calibrated with the virtual camera, got the green screen, and can run it all through OBS and view myself in third person accurately mixed into the virtual world.

Now, I'm having trouble with setting up the foreground layer (this is what would make the virtual hands or objects I pick up visible above my webcam footage).
I'm using the game Stand Out VR to experiment. It's supported through the SDK for mixed reality and I've seen it working in other videos.

I get the four-way feed from the SDK, with the top left and right quarters having what I need (the objects that I need to use as foreground). But I can't get to properly use them, nor successfully mask the layer.

I use the Mask filter on the foreground channel, but no matter the combinations of options I try I never get the wanted result. I've followed a handful of guides, most refer to using the Substract filter. I don't seem to get the desired results this way.
I don't really know which of the upper quadrants to use, I thought that was the top right one to define the mask, them the top left one on top of it to provide the actual graphics. But it won't work.

Regarding the use of the Crop filter in this Foreground layer, I'm lost as to which resolution I'm using. LIV tells me I'm running the game (VR feed) on 1920x1080, which is probably the four-way screen I get from the SDK. But when I enter the halved resolution to crop the right quadrant, I don't get the right size. Is this related to the webcam resolution/ratio I picked in the LIV setup?

Moreover, in my latest attempts, I couldn't get both the foreground and the background layer to have the four-screen output, just either. And still couldn't get to make them transparent.

Please help!

[𝚛𝚞𝚞]

Hmm, sounds like you're trying to use my old alpha filter!

I'd love to jump on a call or something and help you get set up, pm me on Discord: Ruu#9999

[Fdruid]

Ok, I'll look you up, but basically I'm using the latest Steam version, and OBS version too. Why would it have an outdated plugin?

[Fdruid]

Wait, I put in the watermark removing key, could it be that it points to an older version?