I can't provide any useful feedback on the fuel selector valve.
But I'll share what I did to eliminate the "normal" fuel selector valve, and have run for more years than I'd like to admit with great success:
Install an electric pump near each tank. Also install a canister-type filter/separator upstream of each pump to filter the crud upstream of the pumps. Install a check valve on the outlet of each pump, and tee the outlets of the check valves together (and then on to the carb). Put a "last-chance" filter at the inlet to the carb. Use a two position switch to switch operation between the pumps. I did this through a relay located on the transom, to keep the wire gage from the dash to the pumps at a reasonable size. Don't forget fuses for each pump, also at the transom. The check valves prevent fuel cross-over from one tank to the other. And if you fail one pump, you still have another to limp home (assuming you have enough gas in the tank on the working fuel pump

). So it's also a measure of reassurance when you're 20 miles down the lake/river, and the sun is starting to go down, and there's not another boat in sight.....
Something else I added later was a normally open microswitch on the secondary lever on the carb. When the secondaries open, this switch closes and actuates a separate relay, which energizes both pumps. It helps keep the tanks at about the same level during heavy throttle application, since the wife doesn't keep track of stuff like that when she's pulling me behind the boat......
Just an idea for ya.
Matt