> We plan to use a headless 3.8 image on a debian Sarge server with a
> 3.9.7 VM.

We run all our images (except those on seasidehosting.st) with a VNC
server. That makes it much easier to debug and update the code on the
fly.

> - Any reason to use a 3.8 image -- like more stability?

A lot of people are using 3.7 because of its stability. I wouldn't use
3.8 unless you need support for special encodings.

> - Any reason to use a 3.9 image -- like essential bug fixes? (we do not
> use Traits)

3.9 fixes the multilingual issues of 3.8, so I would prefer 3.9 over 3.8.

> - Do we need to strip or shrink the image (and if yes, how)?

No, unless you want to run 1000 images on the same machine.

> - Or is it best to start from a small squeak image (and in that case
> which one)?

Usually I start from the basic image.

> - Are there subtle performance tweaks, (made up example: closing all
> windows in the image)?

Yes, it is important to close all windows, remove the flaps, etc. else
you sooner or later run into troubles.

Cheers,
Lukas

-- 
Lukas Renggli
http://www.lukas-renggli.ch