Override source URL of cask during installation only

[3x071c]

Output of brew config

$ brew config
HOMEBREW_VERSION: 4.4.23-40-g287d8b4
ORIGIN: https://github.com/Homebrew/brew
HEAD: 287d8b402107039c1fc6389f2892ad15ab33fdc9
Last commit: 41 minutes ago
Branch: master
Core tap HEAD: 0733f90fb846039167288d044a12c318525f0fc9
Core tap last commit: 6 minutes ago
Core tap JSON: 04 Mar 20:28 UTC
Core cask tap HEAD: fea39a77d96e0155f98440040df79f828dc26ab0
Core cask tap last commit: 41 minutes ago
Core cask tap JSON: 04 Mar 20:28 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_BAT: set
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: vim
HOMEBREW_MAKE_JOBS: 10
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.3.7 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.3.7/bin/ruby
CPU: deca-core 64-bit arm_firestorm_icestorm
Clang: 16.0.0 build 1600
Git: 2.39.5 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.2-arm64
CLT: 16.2.0.0.1.1733547573
Xcode: 16.2 => /Applications/_SYNC/Xcode.app/Contents/Developer
Rosetta 2: false

Output of brew doctor

$ brew doctor
Your system is ready to brew.

Description of issue

I want to (temporarily) change the source url a cask is initially installed from. In the case of IconChamp, there's a fork by one of the developers which hosts newer versions (1.3.6 - 2 years old, vs 1.5.1 - 2 months old). I don't mind it being overwritten by homebrew if the official appcast ever gets updated.
Currently, this appears to involve several steps:

$ brew tap --force homebrew/core; brew tap --force homebrew/cask # if not already
$ brew edit iconchamp
Editing /opt/homebrew/Library/Taps/homebrew/homebrew-cask/Casks/i/iconchamp.rb # replace the url
$ HOMEBREW_NO_INSTALL_FROM_API=1 brew install iconchamp
==> Downloading # ...
$ cd /opt/homebrew/Library/Taps/homebrew/homebrew-cask && git reset --hard HEAD && git clean -d -f # clean up

Interestingly, when prompting Claude it hallucinates(?) a flag which would save all this effort, using brew install --cask-url=<new url> <cask name>. I couldn't find any reference to this flag explicitly in this org or the docs, and it errors as unrecognized when used.
Perhaps a set of flags to overwrite certain options of a formula/cask once could be introduced?

[SMillerDev]

This really looks like a case for a tap. There isn't really a clean way to make something install other software than it was written for and still work correctly.