For the first tropen camo, May 41 to April '42, I use the following.

My RAL 8000 mix with Tamiya is 40% Dark Yellow, 40% Flat Earth and 20 % Yellow Green. I adjust this by eye to what I think looks best. If I go too green I add the brown color and sometimes add a drop or two of Orange. I perceive the color as a golden brown with a twinge of green.

I mix RAL 7008 60% Tamiya Khaki and 40% OD. To that I add some Yellow Green to taste.

Vallejo Model Color 70879 Green brown is spot on for RAL 8000. It can be airbrushed if thinned correctly with their thinner. Russian Uniform 70924 50/50 with Khaki 70988 is a good RAL 7008.

Model Color airbrushes well over a good primer. I do not thin it as much as I would thin Tamiya.

Vallejo RAL 8000 Green Brown Surface Primer is good out of the bottle. I see it as a bit too green, you might be ok with the color.

If we're talking the late tropen scheme, for RAL 8020 I mix Tamiya Buff 60%, Flat Flesh 30% and Deck Tan 10% I lighten this with white to suit.

RAL 7027 is a bit difficult to pin down. It seems that paint manufacturers render this color differently. Since it is referred to as Sandgrau, Sand Gray, I add a drop or two of Tamiya Khaki to the RAL 8020 mix. That lends itself to a slightly darker slightly greener mix. In my mind it looks like what I see on B/W photos as far as contrast between the two colors (not much) and hue based on the few color photos available.

G

It would depend on when it arrived.

Tamiya's 232 is an early model (1. or 2. Serie as I recall) so if DAK had that model it most likely arrived in Dunkelgrau and was camouflaged quickly in theatre after arrival, as the Aufkl. units were deployed first. Some were camouflaged with mud, which obviously wore off easily; later paint was probably used.

Later versions would have been factory painted in the Tropen schemes prior to shipping but you will need to do some conversion work if you want a 3., 4. or 5. Series example (and I'm not sure how many versions were sent).

The Panzer Tracts book is probably the best guide to differences and production dates and mods and the Nuts & Bolts one has lots of photos as well. There was also a Museum Ordnance Special by Jentz, although it can be hard to find.

That's what I'd be doing. By the time 8020 was being applied it wasn't over Dunkelgrau any more.

I'm a strong believer in photographic evidence. I'm also willing to accept that some vehicles were shipped to Tunisia in grey and overpainted in theatre if not originally intended to be sent there if you have evidence of that.