Have had my 28" for a few years now...here's my best advice
1. clean before and after use (and when I clean I turn the heat on low, scrap it down and then use water and steam clean)
2. after you clean before covering wipe on a thin layer of oil and let it smoke off then let the entire thing cool down
3. get a cover ASAP
You'll have hot spots, so when you season don't crank all the eyes to full heat. My unit has a total of 2 burners and even with them both on low the surface reaches 350-400 degrees with no issue. You can always get 'em a bit hotter, but once they are hot it takes forever to cool back down. Start on the lowest setting and then work your heat up if you want it higher.