Web filtering solution, help!!!

Hi guys,

I looking for some suggestions here about the best option for a web content filtering solution.

I want to implement it for a small congregation so they can block everything but their website, so as you might guess I'm doing it for free and that also mean I'm looking for the most cost effective solution. I don't mind paying for it but if it could be a free open source or something like that even better so I don't have to worry about it not working because I didn't pay for it for any given reason.

Basically I want to redirect any attend to access a website to a custom web page with a list of websites that guest users are allowed to browse, most users will try to access through mobile devices so it has to be mobile/WiFi friendly.

I have tried with PFSense/Squid (real nightmare), PFSense/Pfblockerng-devel and OpenDNS with no success so far. The easiest way so far has been OpenDNS but as with all of them HTTPS is a real pain, because of some websites like Facebook implement HSTS instead of getting the block page redirecting they get the SSL certificates error and that's not something you will want for your guest users plus I won't be able to redirect them to my custom block page, OpenDNS for this problem was the most effective by just installing the certificate in the computer but that would work in a home or business environment but not in a guest environment like a guest network.

I have been trying to do this for weeks now with no success so you could please give any suggestions I would really appreciate it.