Toom2, I'm planning to play the rules unchanged, as the footprint of a 32-figure unit in 15mm will be slightly larger than 8 28mm figures.
I've got the figures to play some test games set in the Sudan, but still haven't found a range for the AZW that really fits the bill: OG15 comes close but I'm really not sure about the look of the British infantry (the helmets just don't look right), there's no sign of Blue Moon adding to their initial launch and most of the older ranges are either lacking variety of poses or particular troop types.
The rules are great fun and needed no real changes to upscale to such a large game, and only a couple of minor tweaks to better represent the particular characteristics of the battle (for example, we downgraded the NNC more than usual, and added a scenario-specific reaction test for them to see what happened when Zulus first came within charge range).