Effects Tab multiple positioners

How do these work? I have a bunch of interview footage with subtly changing exterior light that I need to balance, and really miss how I was able to do it in Lustre. I’d set the A playhead on my reference shot and then march down the list of shots with the B playhead, toggling between A/B with a hotkey to dial in the match. Is this possible to do with the multiple playheads/positioners in the Effects tab somehow? I can’t find much about them in the docs at all. I know I can approximate a similar workflow with grabbed reference frames and the compare bar, but that is extra work that slows me down from how I used to be able to do it.

Talking about these:

Can I somehow put them on different segments and toggle between what I’m viewing and is going to the broadcast monitor with a hotkey?

Thanks in advance!