IPS is limited to files 16 megs or smaller (minus a few bytes), and also does not handle relocations (like you might get inside a Wii ROM or file, especially archive files, on the Wii that uses pointers).
To that end best not to use IPS. If you have seen it used on anything on the Wii it is usually an individual file with a small mod that it is used for.
There are however plenty of patchers that can handle large sizes and relocated data. Xdelta is popular in a few circles, bsdiff also does good stuff.
Encryption of discs on the Wii is however a problem (there is a reason most mod installers patch IOS rather than just outright write a modded IOS module into place. Likewise for disc based stuff people will be told to fish out files with wii scrubber, https://wit.wiimm.de/
or the like, though that also means people that insist on downloading WBFS files, super scrubbed isos and the like can also play without having to rebuild things, which was not actually an option until somewhat recently), and if it is also going to be the case here then you get to replicate that method.
I prefer to give people two choices
1) A nice batch file and program that can tear about the ROM/channel/ISO, patch everything for them at file level and stitch it all back together. Batch file is Windows but nothing stopping you for repeating for the various other operating systems you care to do it for, don't know what there is for Android.
2) A list of files to patch, a bunch* of patches for said files and a link to the patching format. This is OS agnostic but harder to implement.
Nothing stopping you from having 2) as a nice big NFO/readme inside the download for 1).
I have seen the file system aware tools combined with a patcher in the past to make essentially another patching format and custom patcher (Jump Ultimate Stars on the DS being a nice example).
Some people on the Wii also abuse various exploits to run patching programs for their hacks (today smash brothers is probably the most notable but there were many others prior, during and since). Make one of those if you want, however I am not a fan of seeing them as the exclusive means of doing it.
*bunch of patches is simple but it is also possible to say note that something like a tar file is almost a bunch of files just put together and predictably so. To that end you could explode something into the however many thousands of files, tar the lot, patch the tar and then. If the patcher has some kind of content detection (think like compression reading forward or back) it might end up as a smaller patch size overall, though if you do have 8 gigs that might make things larger or shoot up patch making time into the days if you have to do 8 gig read ahead/look back for thousands of files.