Frank I grounded my ICOM with two dynaplates one port ,one starmord ,3" X 12". and used 3" X .010 copper strap.I was assured by H F radio on board that THIS WAS BY FAR THE BEST GROUNDING SYSTEM you can contact them at 510 814 8888 or www.hfradio.com good luck Roscoe
I ran 3" copper strapping from the tuner in the lazarette up either side of the hull under the deck. The foil mostly hides under the trim panels and was easy to run. Seems to work fine as I had HF voice and Pactor 3 email and grib files all the way from SF to Kona.
HF radios don't need a ground like an electrical circuit but a counterpoise. The counterpoise is actually more effective if it is above the water line. Not to say that running the tuner ground/counterpoise connection on your tuner to a thru hull won't work, it's just not the best way to do it.
The cheapest and easiest way to get a counter poise is with a system called KISS. It's a bunch of wires in about 15' of shrinktubing. Just connect it to your tuner and lay out the Kiss tubing. $160 and about 5 minutes of labor.
I'm running an ICOM 718 ham radio with a SGC 230 Tuner into my backstay antenna. Have a Pactor IIE with Pactor 3 upgrade for email and grib files.