Hotspot - Trial User as the main choise

Hi all,
i’ve to configure an hotspot that give free access (without authentication) to all users.
Yes, without any restriction (.. at the moment .. we can suppose that some rules will be implemented)

I’m studying some script to get mac address form the DHCP leases, use it for the mac authentication of the hotspot, and reset counters every 00:01:00…

Do you think that i just can use Trial User Function?
In this case, how can i modify login page to have a personalized button that “start” the login?

Thanks for your helps,

dstncl