In terms of RLM colors, Gunze is the most accurate and best to use overall IMO. I would use those if you can find them. You can spray finer detail and they don't have the "tip clog" problem Vallejo paints do.
I've used the Vallejo Olive Grey on an E-4 and it looks very close, although it has a more olive hue than dark green. But its about neck & neck with the Gunze 71. Tamiya XF-61 would also be a good close match for RLM 71 or 83 if you don't want to do any mixing.
The main ones that are not accurate that I've used are the RLM 74/75 colors which are way too dark and lack the green/violet hues seen on the real thing. The RLM 65 is a little too blue IMO so you might wanna tint it with white a bit. But I think they reformulated the RLM 75 so its more correct now.