SdKfz 6/3 Diana for the Afrikakorps – but how?

As if the decision about the Sd.Kfz. 7 wasn't hard enough, a few weeks ago I found this one, the Sd.Kfz. 6/3 Diana. It is based upon the Sd.Kfz. 6, which is basically a lighter predecessor of the Sd.Kfz. 7 "only" being able to tow 5t instead of 8t. It was fitted with captured Soviet 76-mm divisional guns model 1936 (F-22) and an armoured superstructure was build around it.

The Sd.Kfz. 6 is not available in 28mm, the Diana can only be bought as model kits or 15mm, but it was in service in the Afrikakorps. So it would fit in the project and would be another great field conversion and outstanding rarety. Yet, how to approach this project?

The Sd.Kfz. 6 and 7 look very similar and the chassis is in smaller scale indistinguishable. Mostly the road wheels and sub-structure of the box is different. So I probably could get away with using the Sd.Kfz. 7 kit again and scratch build the box on top. The arches could be build by using the pieces from the Opel Blitz/Maultier kits.

I found on polish modelwork and russian modelling pages these pictures, and the first picture gives you a good idea on how to scratch build the superstructure.

As for the gun Soviet 76 mm gun, which would be the 1936 F-22 variant, is a bit tricky as well. Warlord Games covers the ZiS-3 76mm gun, as does Crusader Miniatures, which should be close enough, yet the ZiS-3 features a muzzle break and a support cylinder on top instead of the two bottom ones. Those would need to be modified.

If I went for a dust cover / tarpaulin for the box, the whole build would be come much easier. I guess the road wheels could be modified by removing the small beams on the three outer road wheels.

Any suggestions on how to achieve this conversion in 28mm and what available pieces to use as a start?