Those trees...I mean that forest now :D Is looking even better.

I know it's not finished but are you planning to add a bit more green to the roots? like moss in places?

I have also looked back over previous mock up of defined shafts of light shining through the Dagobah trees by others (not the team). And although I really think that effect is great I am not so sure it is exactly the right thing for the scene (to be very defined shafts of light) that is if you are going for recreating that effect from the theatrical version.

Anyway I have searched through many photo's to find a good reference and real world replication of the original matte in terms of sun and fog / mist and a subtle but beautiful lighting effect that is not "In your face". So I hope this can be of some help as a real world match

That is not a suggestion that is trying to be helpful. And I am sure you know what you want to achieve with the shot by now I just hope that is a good real world reference that can help you. But I am also now wondering If you are going for a real light source to re-create the original matte or do a green screen or perhaps combined both real and artificial elements?

It's going to be a tough cookie to keep Luke and R2 well defined and lit if you have a strong Back lit set by sunlight through trees. I guess the SE decided to give it a look more like the sun was coming from the other direction without altering the other shots. I think this x-wing shot will be tricky lighting wise If you go for re-creating the theatrical matte with a physical model. But this does get me excited for them.

sun is on the right on x-wing shot?