@Bassman2003 - Nice video. Best one I have seen covering spunding, purging with fermentation CO2 and closed transfers.
@erichsmith - Since you are a professional brewer, I assume you have access to plenty of Sanke couplers. So why not use them? I ferment in a 1/2 barrel Sanke keg, with the spear in the keg, and use Sanke couplers, with the check valves removed, to ferment, purge the serving keg with CO2 from fermentation and closed transfer. See attached video for its configuration during fermentation. The blue handled ball valves on the fermentor allow me to change from fermenting to a closed system transfer to the serving keg.
This setup is more economical than those shown above assuming that you can borrow two couplers from the brewery if you need to.