It's great that your oven can hit 650. That gives you a wider selection of stones to work with. Could you tell us about your existing stone? Brand? Thickness? You're not using a screen, right?
The way to match the top bake to a fast bottom bake is to use the broiler during the bake. If you don't have a broiler in the main compartment, then that complicates things, but isn't insurmountable.
I feel like we're going in circles with the whole flavor thing A while back we talked about flavor, and then, more recently, you started this thread with a formula containing 1.55 salt. You can't talk about flavor issues and use 1.55% salt Let's try this one more time.
Maximizing crust flavor for NY style
3% vegetable oil
Malted flour (preferably bromated, such as Full Strength or an All Trumps/all purpose blend)
Minimum of 3 days cold fermentation with appropriate quantity of yeast (dough should just about double in the fridge and then triple by baking)
Broiler during the bake for good top browning
Temperature necessary for 5 minute bake, top and bottom. If you want something crisper and more golden brown, go with a lower temp for a 6 or 7 minute bake
More extreme steps (shouldn't be necessary)
More than 5 days cold ferment
Appears some circles have been made, my fault.
I use a thin stone, I think 3/8" thick. I dont have broiler control, i modified the t-stat on a cheap counter top bake oven to get the 650 F. I probably will modify the broiler coil for manual or auto control. The bottom and top element both come on at the same time, so it's like a preheat condition.
My idea is to build a simple controller, relays, and time delay relays, that will turn the broiler element on the last 2 to 1 minute of a set bake time, which is 5:30 to 6 minutes for me now. I would make the broiler on at end adjustable and play with it.
Glad you mentioned 2% salt, i tried it then went back to 1.5% based on a comment by Pete-zza I found, stating 2% max for him for salt, because he felt too salty of a taste, and I don't like getting to a max value, so i bumped it down to 1.55% salt.
However, the 2% was NOT salty at all
I will return to 2% salt. 3% was definitively salty.
Got all covered in your "Maximizing crust flavor for NY style" except the 3 day ferment, after several attempts, we found no difference in a 24 referent. I know it's common knowledge here, so it has to be us, not you.
Malted barley, honey, Molasses instead of sugar?
You never mentioned sugar? You recommend it??