Just looking at the NYCFC 2018 home attendance figures.
Sunday 5 pm v LA Galaxy - 26,221
Saturday 3.30 pm v Orlando - 18,854
Wednesday 7.00 pm v RSL - 18,603
Sunday 6.30 pm v FC Dallas - 22,115
Saturday 1.00 pm v Colorado - 21,494
Saturday 7.30 pm v Orlando - 22,103
Saturday 12.30 pm v Atlanta - 25,268
Total Attendance = 154,658
2018 Average = 22,094
2017 Average = 22,321
2016 Average = 27,196
2015 Average = 29,016
I was originally thinking a 30,000 seater stadium for NYCFC (if it ever comes to fruition)
However 25,000 seats is looking more like the right amount.