Thank you all, for your responses.
Below is link directly to Gordon West White Paper on counterpoise.
Very interesting read.
Still looking for previously read analysis of KISS by a skeptical, and obviously technically savvy US amateur radio operator.
Antony: I agree with the simplicity issue. The KISS offers this and has advocates. There are also those who claim they had terrible experience until they added a seawater based connection.
Vic: I do not know the layout of the Oyster 15. I assume your installation of the radio and control head is on the Oyster 15? Based upon your description, our NC 33 configuration options appear to be different.
I have considered mounting the radio transceiver below the salon seating in main salon, and control head at the pilot house Helm. The issue with this is that sitting and using controls might be mildly awkward when sitting and communicating in harbor, getting weather fax, etc. The advantage is the controls would be accessible while underway.
Re: counterpoise: I have several options for using copper foil to connect to underwater thru- hulls as well as a bronze plate near keel. I admit concerns regarding electrolysis.
However, my biggest question has to do with the antenna tuner (AT-140), antenna lead and the related potential for RF exposure to humans within cabin. If AT is installed in the aft hanging locker, and antenna lead wire is run up to main mast backstay located on cabin top, there appears potential for RF in area of aft cabin and in seating within the pilot house. So, as a less elegant option, I am considering installing AT on cabin ceiling directly below where antenna lead would exit to connect to main mast backstay. This would be less aesthetic, but shorten antenna lead and put RF above people sitting in Pilot House. Does my description make sense? Open to suggestions and again, appreciate comments.
Again, thank you for assisting me with thinking about this. I still hope to get photos and hear from people who have installed SSB in NC33.