Dropbox and Truecrypt

I want to have both the convenience of Dropbox and the security of Truecrypt.

Say I create Container X.tc and then put it in my Dropbox folder. I can now access Container X from anywhere in the world with an internet connection. But I want to routinely change information inside the container, keep it secure, and have the updated changes from anywhere in the world. So I mount Container X and put Grandmas Secret Cookie Receipe.doc into the container and then dismount it. I un-check "'Preserve modification time stamp of file containers". How safe is my data in the following scenarios:

1) My Dropbox account is hacked and the attacker gains access to all my files stored on Dropbox.

2) Someone gets access to Container X when it is unmounted on two separate occasions. The contents HAVE been modified in the time period between. I remember the Truecrypt warnings saying about if an attacker has two versions it makes decryption easier but I can't remember what for.

For arguments sake assume the following:

1) Truecrypt isn't breakable
2) A perfectly random 64 character password is used
3) Physical security is perfect i.e a FDE harddrive inside Fort Knox (Ok so thats stupid but I just want to make clear I'm only concerned in knowing about the web based vulnerabilities of this).
TLDR: I want the convenience of Dropbox but want to have the safety level