Current seating 4660 chair backs in 15 sections. Including box seats that's right at 300 seats per section. Including bleachers capacity currently at 7200.
Renderings show 26 sections including both tiers. Figuring total of 600 per tier pair (top and bottom) gets you to 7800 in the grandstand. I'm guessing is closer to 8,000. Using the record crowd, accounting for chairs and bleachers, there were at least 8,686 in the outfield and suites. Adding that to my guess of 8,000 puts capacity over 16,700. I think that is conservative because there will be more suites, etc., and then there is the berms on each side. Unofficially I think you can put 20,000 in the place.