Reducing a users speed doesn't mean they will reduce their data usage.
Example 1: Someone who watches Netflix 4 hours a day will transfer the same amount of data at 36 Mbps as they would at 28 Mpbs, if overhead is the same. Netflix streaming bandwidth doesn't use data as fast as either connection is capable of, so the user wouldn't see any difference.
Example 2: A user downloading 50 movies at 1.5 GB each will still transfer at least 75 GB of data at 36 Mbps as they will at 28 Mbps, if overhead is the same, but it will just take longer at the slower rate.
Your suggestions make the connection less efficient, it doesn't reduce the amount of data the user transfers.
I can see how disabling the Nagle Algorithm setting can change the average latency for small packet based connections (less waiting to fill bigger packets), but it doesn't reduce data transferred. With more packets and packet headers, it would actually increase total data transfered.
To really reduce the amount of data transferred, users have to change what they're downloading and uploading. Playing tricks with protocol options leads to minor changes in data transferred, usually leading to increases due to more overhead. --
If it's important, back it up... twice. Even 99.999% availability isn't enough sometimes.