Here you can see a close-up picture of the FT-897 whip mount that I have installed, using a Hustler quick disconnect and some plastic isolators. It is connected in parallel with the tuner's so239 antenna connector.
The other SO239 connector by the whip mount is for VHF/UHF and is not yet connected to the radio.
I am also thinking about the possibility of preparing a 4:1 impedance adaptor for the whip mount only that would be connected with a smal jumper. What do you think? Does it pay?