do you have access to a silkscreen on a jib or something to diffuse the light for even keying?
You’ll want to get a light meter for getting 60 IRE. This is for 2 reasons.
1. green or blue saturation once turned whitish, is no longer keyable.
2. no camera can do 30 f-stops in latitude so you won’t be be rotoring blown out highlights for a long time.
This means that you will not only need to diffuse the light on the actor for even lighting, but bring its brightness down so that it matches the IRE of the background.
If you don’t get a light meter, there’s not much point in attempting this complicated shot.
Keying green over green seems like giving yourself extra work. Can you get blue suits instead? AE supports duplicated effects though.
basic keying tips
https://generalspecialist.com/2006/10/greenscreen-and-bluescreen-checklist.asp
https://technicolorsoftware.hostzi.com/