Hi Mark.
I dont go to greek restaurants around here, but was in Greece earlier this month on vacation. I tried both gyros and souvlaki (gyro was a choice between chicken and pork, and souvlaki was a choice of chicken, lamb, or pork) and I have to say I think souvlaki is the healthier choice. My brother ate the gyros constantly and I noticed they were greasier than my souvlaki. Souvlaki is made with leaner cuts, marinated in lemon juice, olive oil, and oregano/spices, and gyros utilize fattier cuts to keep the meat moist yet crispy thruout the spit-roasting process.
Since you asked, and that was the original intent of this thread, I would consider switching to a souvlaki skewer (one skewer would be plenty, and would likely be sold as a side-item) instead of gyro meat to accompany your salad, in the absense of actual nutritional data provided by the restaurant.
Just my thoughts, having just been in greece
regardless, a salad+gyro meat is still a good choice as long as its not too big a serving of meat. and its def. better than eating a regular gyro fully loaded!
Keep up the good work.