In the world of encryption I'm affraid there is no such thing as over kill.

Some other encryption tips to ensure success.

Firstly the OS. Forget about using a Microsoft OS to do your encryption. Use a Linux OS as this is open source.

Do your encryption on someones elses PC (best approach after pulling out the network/modem cable so it becomes a stand alone machine). To do this boot of a USB memory card with something like Ubuntu.

Do your encryption with something like PGP or Truecrypt. Do not use a public key but a private one. The best keys are generated are those ones generated randomly. This can be done by using a MBX3S connected to your PC and by using the data generated by the MBX3S and then converting the randomness of the data to generate the key into a plain text file . Use a long key i.e thousands of bits in length.

Hide your encrypted files in plain sight. XOR the lsb's of a .WAV file then re-encode into a apple .mp4 lossless audio file

Send your plain sight files using someone else's network. i.e. using someone else's unsecured wireless network.

Destroy the original unencrypted files by reformatting the USB memory card and then re-installing the Linux distribution on to the USB memory card. Hide your USB card in the heel of your shoe.