Dude,

Before you even atempt to upgrade. First download a backup from your host control panel. Second download the database mysql from your host control panel or phpmyadmin. These are a must. Do not even think about upgrading without doing so first.

If you have not manually tweaked, altered, removed, adjusted or whatever you want to call it actual code of the script, then simply overwrite the 6.1.0 files on your server with the 6.1.1 patch. Follow the instructions, to run upgrade. They do leave see more out the part that you need to delete upgrade.php and the upgrade.sql file when done. Do not run upgrade.php 2x, or it will mess up your database.

If when you say you have a spend a lot of time tweaking...hoping you are referring to your site...jk.

Anyway if you have modified, altered, added removed certain code associated with downloaded mods from expertzzz or your own, then yes you will need to manually copy/paste, cut/paste the differences from the patch files to the ones on your site.

This is a real time consuming process. If you don't have any mods then overwrite. Sometimes it's actually faster to over write and re-do the tweaks. Depends on how many and what the situation is.

If you don't have many mods or customizations consider yourself very lucky.