XFlak has released, what seems to be a total solution for Wii Owners - Been having a Play and it's seems to be, all it claims to be.
Not only does it sort out what ios's you need it also prints you a custom guide....

ModMii for Windows
Version 4.2.3

Formerly Known As NUS Auto Downloader

by XFlak


The Interactive Download Wizard
makes Modding Wii's Easier than Ever!

Complete With Custom Guide Generator

Use this program to easily, automatically and legally set-up your SD card with the required files
to fully softmod ANY Wii (4.3U/E/J and Below & 4.2K and Below), and up/downgrade to firmwares 4.3, 4.2 and 4.1
(Support for all wii's: U,E,J,K and even Region Changed Wii's)

When using the download wizard,
a custom guide will be generated based on the users answers to a few simple questions

Literally run the program once, let it download,
and you have all the files you need on your SD card to modify your Wii