I am interested in seeing what happens with you. Alot of programs need some kind of inclination of academic prowess. If you dont have a class rank and the "new board format" is your only tangible academic item, it might be tough.
I dont know if the programs around the country are really aware of the change in the way the board exam is.
I know our program really looks at board scores when an applicant goes to a school w/o a class rank. And an 83 on first glance is not as competative. I hope that the national board people send out a memo to programs explaining the new format.
I think a lot of the applicant taking the "new format" are going to suffer because of this.
To answer your first question, apply to as many places as you think you can afford. Remember, you also have to travel to these places for interview. It gets costly.