1. Don't season the steel. A pizza launched from a floured peel, if baked at the right temperature, won't stick to any surface. Also, at the temps you're working at, the seasoning will eventually bake off.
2. Sticking= burning. When the hearth is too hot, the dough will char too quickly and, at the spots where the char gets very black, it will stick. You can get leoparding on the base without torching the bottom with extreme heat and having the dough stick on. If the dough is sticking, you need to dial down the heat. If you're getting leoparding in the oven with a 600 deg. plate, why are you pre-heating the plate in the grill to 700?
3. Whole wheat flour is usually malted. Water encourages enzyme activity/sugar formation. High sugar doughs almost always burn at high temps. In a malted, elevated hydration dough baked at a high temp, the window between properly leoparded and burnt is minuscule. One second it's perfect, the next, burnt/stuck on. If you want to use malted flour and avoid burning/sticking, then you'll need to back off the water and/or the fermentation time and/or the heat.
4. Evaporation makes for crispy crusts. The faster the bake, the less water evaporation, the softer the crust. The slower the bake, the more water evaporation, the crisper the crust. The same dough that crisps up in 7+ minutes of baking will not crisp up in 3-4 minutes. In fact, it's very difficult, to get crispness with quick bake times. <2 min. Neapolitan pizzas are never crispy and 3-4 min. NY style pizzas are rarely crispy. Neapolitan is puffy and soft and NY is puffy chewy. Both are floppy. Coal oven/Neo-NY pies can be a bit crispy, but the crispy areas are usually confined to the areas with big voids.
The more water in the dough, the greater the tendency for softness in the final product. If crispy is your goal, you need to dial the water back- way back. 60-65% hydration- max.