My thoughts:

If you're wanting MPG, make sure you have a heat riser passge thru your intake, especially with TBI systems like the P-J. Heat helps atomization, and atomization = better MPG.

For a cam, get a Lunati Voodo 60302 or something similar. Err on the small side.

If the P-J has an O2 sensor setup (and hopefully it's a wideband), turn the FP UP, not down, IMHO. Increasing pressure increases the atomization, which helps MPG. The ECU should watch via the O2 sensor and then shorten the injector pulsewidths to reduce the delivered fuel back to target. Depending on the P-J's learning capacity, this may take a few days of running to adjust .

Depending on how much you can program the air-fuel settings, leaning the AF to 15.5-16 on the highway will help. You will need more ign advance at those spots to help the burn. If you get a misfire the AF is too lean (keep in mind a lean misfire will make the O2 sensor show rich, so don't get confused when it happens).

Don't get terribly concerned if the engine wants to be a little rich at idle. That's somewhat normal, some engines aren't happy idling at 14.7.