Bruce,
I like you figured since it was a "zero turn" mower.....I should be able to perform a 180 degree turn with it(I have a Segway Human Transporter and I can do one on it:0)
Then came the learning curve of, as mentioned, keeping both wheels turning to avoid making "divets" in the grass. I mowed two "circular paths" around the yard(to give me an already mowed turnaround area on both ends) and then began a back-and-forth mowing pattern. I would go all the way to one end, stop, start going backwards(with both levers) slowly and then push one side barely forward and obtained a decent 180 degree turn with insignificant turf damage(no visible divets). That's not to say that occasionally I still leave a small divet and I haven't tried user Kenny V's suggestion to do the 180 when completely stopped...but may try that the next time I mow. But, all that being said, I tend to agree with user Ric(and the Scags article) that the "Y turn" may be just as efficient(if not more) than attempting a "true zero turn" and aside from the concept in my first sentence it will accomplish a quick change of direction and keep straight lines back-and-forth in the mowing pattern(which is basically the desired result). I have a whopping 16.5 hours ZTR driving experience, so like you I'm still very open to suggestions by others on these forums(especially seasoned ZTR users like Ric & Kenny V) about the best/most efficient way to drive these beasts. Just like they said, experiment and practice....practice....practice!! And we'll "have fun" mowing our yards while practicing:0)