You don't need to direct to me!
I appreciate the compliment, but there are several regulars around here with more compost expertise than me, especially for dealing with large quantities of stuff.
But here's my take on your questions:
Good size is sort of a 3' cube to a 4' cube. Much smaller than that, it doesn't heat up as well. Much bigger than that and it's harder to manage, to keep moist in the middle, etc.
Nope, can't burn your plants with it.
I'm your in-town neighbor in Cincinnati.
Incidentally the straw and grass clippings is a good start (brown + green). But we generally say it is good if no more than 10% of your pile is any one ingredient. You have as noted 50% one ingredient. What you want is for your finished compost to contain a full range of all the macro and micro nutrients and all the different soil biologies and to be pretty balanced re pH, fungal-bacterial, etc. To accomplish that, it helps to have a diversity of ingredients going in.
So look around for what else you can add -- kitchen scraps of course, one bucket of kitchen scraps has a whole ton of different ingredients in it, leaves, used coffee grounds, used paper towels, manure if you have access to it, etc etc. Your materials will break down better and create a better finished product with more diversity.