We have an ICOM710 with an AT130 tuner mounted in the hanging locker at the aft end of the pilot berth. Our antenna is the main mast backstay. The antenna lead goes through the head access to the base of the mizzen mast and up the mast a few feet and out a hole to connect with the insulated main backstay. It works well.
We initially tried the triatic stay, as the Furuno weather fax was connected to it, but it was worse than useless with the ICOM SSB, so when we re-rigged the boat a couple of years ago, the insulated triatic stay went west.
Interestingly, did you know, that none of the Super Maramu rigging is connected to ground ?
So apart from the risk of a crew member getting zapped, connecting the tuner antenna wire to any part of the standing rigging would work a treat!
We insulated the main backstay to avoid problems with crew getting zapped !