Adjusting DHCP Lease duration for pfsense

[Snailkhan]

Hi
I have pfsense with dhcp.
I have captive portal on one of its lan interface there is a zone and there are 10 voucher rolls some are 12 hours long. Some are one week long some are one month. Yet some that are 4 months.

I have 150 IPs for distribution and mostly there won't be more then 50 users simultaneously connecting to guest.

How do I adjust the default  and maximum dhcp lease as per above requirements.

The issue is that I do not want the guests that will be staying for  4 months to daily or frequently enter voucher code if inset dhcp lease duration to say 15 hours.

Also since no layer 2 authentication is used so all people try to connect to the ssid and do not want to starve the dhcp server out of ips.

How is dhcp adjusted so am ip is free.

Isn't there any option in the captive portal of pfsense to clear the dhcp lease for an ip that was connected via captive portal once the vouchers has expired?