between the meet and the spatula does help so it doesn't stick to the spatula (can work without it, but might get some sticking). Don't be afraid to really smash it good and get crispy edges.

I would agree with others to do them in batches. 6-8 at a time. Otherwise they might burn. Use American cheese (I was anti American cheese but have come around after research).

I like to grill onions first (I do it in bacon grease, but any oil will work). Set those aside on the cooler side of the griddle. Start toasting the buns with burners low. Then I do the burgers last so I can put them right on people's buns.