IT resources and bandwidth experiment - is it enough?

Our students are doing a unit involving much internet use (around 80 students in IB Theory of Knowledge course).
How did the IT resources and the school's bandwidth measure up?
Some information - the unit is on a Google Site with links to some video resources (Screencast-o-matic and YouTube), to Google Groups discussion forums and to Google Docs used as a collaborative space. Four classrooms being used, each with its own Fortinet access point, about 20 students per class, with a 600C Fortinet firewall allowing 16Gbps Firewall throughput, up to 3,000,000 concurrent sessions and up to 70,000 new sessions per second. We have a 30 Megabit/second internet connection with 1 to 3 compression which was upgraded to this two years ago - this is a description of it.
So, how did it go?
This is the system resources report on how our Fortigate unit (our firewall) was doing during the heavy load period. Fernando, our Sysman (who provided all this information - thanks!), describes this process as a traffic manager, and you can see it doing really well. Conclusion - enough capacity here.

The following traffic history is from our Fortigate - internally monitoring our bandwidth in a 30 minute interval:

Fernando did a sweep of the classrooms and found some disgruntled students trying to access a Screencast-o-matic video - they had internet bandwidth problems (nb: not wireless access point problems) as well as Java problems (Chrome on Apple, Chromebooks, etc).
However, I noted in following the activity from viewing the collaborative Google Docs that were being produced, that this aspect worked well.
What did it look like from our ISP? Here is the report from the same time:

And here is the problem, our 30 Mbps topping out during this classtime.
So, all the work to upgrade our internal systems has worked, but we need much more bandwidth to cope with our use. Anybody suggest how much?