Extra security for paper wallets I want to transfer my bitcoin to a paper wallet for long term storage. However, with the risk of fire/theft etc. I'm not comfortable holding it as a paper printout. 

So my question (sorry if its too noobie)....why not:

1) create the paper wallet addresses

2) manually write the public and private keys on a piece of paper BUT for the private key, change just one character of the key in a way only I know. For example, increase the 4th character of the key by 1 (so if the 4th character was the number 8, I write it as a 9 on my piece of paper, if it was the capital letter B, I write it as the capital letter C.....you get the idea). So far so good for having a secure paper storage. But what about fire etc...

3) Email the info to my gmail/hotmail account. So I'll always have access to the info as its stored on "the cloud" but is hopefully useless to anyone who hacks my email??

Is there a flaw in my system? Is potentially giving my public address plus 95% of my private key to would-be hackers risky?

Many thanks for your thoughts!
This is extremely risky and not a good idea.

If you just increment one character, there are only about 50 ways to do that.  It would be extremely easy for an attacker to just try all 50 possibilities, and they would find your key and steal your coins.

Even if you change one character to a new random character, that's only 50 * 58 = 2900 possibilities.  Still very easy.  Particularly since the key has a built-in checksum, so that an attacker can tell with high probability whether their guess is correct with a simple computation.

The security of your private key rests in the fact that it is a random one of an extremely large number of candidates.  By revealing most of the key, you reduce that number of candidates to a very small number, and lose all your security.

Don't reveal any part of your private key, or save it where attackers could get it.  Also, don't try to "encrypt" it with any scheme you come up with by yourself (e.g. a substitution code) - those are also extremely easy to break for any reasonably clever attacker.