Re: Having a hard time understanding Traffic Shaping
I don't think you want a Per IP policy for Sales Force but rather a shared shaper of 25 Mbps. If I understand per-IP (which admittedly I haven't had to use), it allocates the specified bandwidth per user. So 2 Salesforce users could suck down your entire 50Mbps and leave everything else crawling.
Maybe to make sure per IP is understood you would want to create a shaping policy that matches all traffic with a small per IP shaper (maybe 5 Mbps depending on your user count) and see if it works as expected. (You'll want to disable all other shaping policies while you test).
To me the expected behavior would be that each user (regardless of application, so you could test this by just going to speedtest.net) should be limited to 5Mbps. That should leave plenty of bandwidth for each user, up to at least 10 users, and that will give you a much more reasonable download speed (though of course keep in mind the difference between Kbps and KB/s).