Nice progress Phil!
I had the luck to stand beside a StuG III and it is a mean machine!
I switched over to building some smaller details on my BPA Su-100.
Built the Infantry Communication Port:

Added an Elf headlight and built the horn.The horn consists of 12 styrene bits and a copper bracket

a build of its own.Still need to add some wiring though:

Built both towing brackets and the saw with its mounts:

Added details on the roof of the casemate, incl. hatch spring rods:

Filled some gaps in the figures with Miliput.
And built a tank driver too:

I'm not sure I'll use the tank drivers figure though- it leaves the large empty interior visible...
And although I can 'borrow' some parts from the Su-122 and T-54 interior kits I have in my stash, building a partial interior will come at the expense of my progress in other Campaigns I participate.
So unless I find some elegant solution, the tank driver is out.
Some full view pictures follow:



Take care!