I'm using Vegas Movie Studio Platinum 17. I honestly don't know how to use the masking/tracking effect, but I'm wondering if I can use it to cut out the green screen space in the shot, which is a moving shot, and a very important shot, but the green screens are poorly lit. Here's a screenshot:

What do you want to replace the green screen areas with?

I was hoping to cut out the green screen areas and have the background image I'd originally planned on using with the green screen for the background, which is a sky background. I was essentially wondering if I can use the masking effect like a cookie-cutter that can be applied to a moving shot, so I just cut out the green screen areas so the background is visible, but I'm not sure if that's how the masking/tracking effect works or not..

Ok what in the image that you posted do you want left in? I ask because I'm puzzled. Usually green screen appears behind something like a face. With your shot it's not clear what you want left in.

@Tim-Boone It looks as if the green areas are quite small. If you just wanted to replace them with sky, you could use a colour replacer to change the green into blue. Or would that not work for you?

Do I understand that you want to reduce the vestigial green areas to transparent and leave the candles as they are?

I would just use a cyan threshold mask something like this; VMSP 17 should have the standalone Curves fx:

@Musicvid VMSP17 has Color Curves, Levels and Color Grading but I cannot find anything that looks like what's in your image from Vegas Pro. Color Grading is probably the nearest but personally it's something I struggle with.

I show the Color Grading Panel in VP19 with the curtain dragged all the way to the left.