If you have preloader why don't you just ENABLE the "skip disc update check" option under preloaders system menu hacks? That's the easiest way to prevent disc upates from bricking you. If you don't have ur wii set up to boot to preloader when you turn it on. just hold down the reset button while turning ur wii on and it'll boot to preloader.
oh and doing this, you're not actually getting rid of the update on the disc, you're making ur wii skip reading that part of the disc. so much easier than patching and removing stuff from the disc. that's the old skool way. lol no longer necessary!!!! are you gonna be burning backups of your games, since you mention having verbatim dvd-r discs I assume you are.