500 is great! You probably have a metal prop. The inertial really helps here. I've typically run wood or light composite (wood core) props and can't get quite that low. Ultimately, you want it as low as it can go without quitting when you tug back on the throttle with a couple pounds force.
HINT: It really helps to set the idle mixture right first. Otherwise, you'll set your idle adjust too high because it will load up after 10 seconds. You know mixture is set right when after 30 seconds of idle RPM stays put and you can goose the throttle and it just slightly hesitates, but doesn't cough.
I don't know anything about slapping pistons.
I have the EFII full system and this fuel ration gauge http://www.plxdevices.com/ProductDetails.asp?ProductCode=897346002719
have not seen any loading up issues so far.
Unless you want to set a land speed record or burn up your brakes, 1000 rpm is way too high when taxiing.
It's almost that extreme in a -4. With a fixed pitch prop, a thousand feet of float wouldn't be surprising at that rpm.My O-320 powered 9A is set at 650rpm (FP metal prop), which works well and doesn't float excessively - the 7A would float even less I imagine.
Lycoming recommends minimizing time at idle RPMs to reduce cam lobe stress, and I believe that is where the 1000rpm guideline comes from - it is not the proper true idle speed though - I'm not sure the 9A wing would even land at 1000rpm!
Chris
Wow...1000-1500. Looks like everybody's doing it wrong.
Mine with a CS prop will probably quite at 750 or 700 but I recall either hearing or reading that Lycoming recommends 1000 or above for idle speed.