[squid-users] reply_body_max_size question

[Danny]

I am running Debian 8 with Squid3 installed (transparent). However, I would like to know a little more about the "reply_body_max_size" directive. I have read quite a bit about it but none of the discussions on the net fits my criteria ... 
(Oh yes, squidGuard is also running around my server somewhere doing what it is supposed to do ... I hope ... )

It is a home setup with the Debian box serving DHCP IP's over wlan0 (which all devices in the house connect to for internet access). 9 laptops, 4 PC's, 7 tablets and 9 SmartPhones (and that is only the kid's stuff fighting for bandwidth supremacy ... ;) ) ... We are all on the same subnet ...

The problem I have (as with most parents) is to limit the kid's download sizes from all over the net. Where I am we have capped internet and have to pay for more cap. 
Currently I get 20GB of data every month and by the end of the month I have purchased in excess of 100GB throughout the month which gets very expensive. 
My son plays games on his PS3 and some of the games (Call of Duty, I think) one player can download another player's in-game recorded video (or something like that) and that eats up the cap.

Currently my "reply_body_max_size" is set to 20 MB in my efforts to curb downloads and save some bandwidth. 
However, whenever myself or the wife wants to download or visit youtube I have to change the 20MB limit, restart Squid3, watch youtube, change limit back to 20MB and reload Squid3 again ... which is a pain in the butt ...

Currently my ACL's look like this:

acl localnet src 10.0.0.0/24
acl localnet_dad_laptop 10.0.0.10
acl localnet_dad_smartphone 10.0.0.11
acl localnet_mom_laptop 10.0.0.12
acl localnet_mom_smartphone 10.0.0.13
acl localnet_son_laptop 10.0.0.14
acl localnet_son_smartphone 10.0.0.15
acl localnet_son_tablet 10.0.0.16

---and so it goes on for all the other devices---

http_access allow localnet
http_access allow localnet_dad_laptop
http_access allow localnet_dad_smartphone
http_access allow localnet_mom_laptop
http_access allow localnet_mom_smartphone
http_access allow localnet_son_laptop
http_access allow localnet_son_smartphone
http_access allow localnet_son_tablet

---and so it goes on for all the other devices---

How can I allow mom and dad unlimited download sizes but limit download sizes for my kids (son, daughter and daughter) and all the kid's friends that visit and sleep over?

Thank You

Danny