So you don’t have a clear solution, but a clear picture of the problem.
It boils down to "let postops choose". This assumes that women will accept postops in their spaces. Some might, but they can't consent for all women.
Also, even if they would say yes, how are women supposed to know if a TIM entering their spaces really is postop? Should they simply believe that people are good and honest, and that preop and nonop TIMs will voluntarily self-exclude?