Neil Short's recent 'Tank turret fortifications' seems to have rather good coverage of these 'Sockellafetten' or simplified pivot mountings mainly produced by Rheinmetal Borsig. Specific mounts were made to take surplus 5cm. 7.5cm & 8.8cm guns. Many other extemporised defences are covered, including pre-made box structures designed to support entire Panther turrets, in steel and wood. Trouble is though I've had the book for a while I've only just got round to starting reading it.
Cheers,
Adam.