Hi,
If you want wire wheels, I say go for wire wheels! They do look great on these old cars (and even some of the newer ones).
The reason I don't use them personally is weight, cost and strength. I prefer an alloy wheel, but that's just me and my cars.
If you do go with wire wheels, I'd say definitely step up to 60 spokes minimum for strength. The original 48 spoke used on TR2-4 are just too weak for regular use and abuse. (70 or 72 spoke would be even better and stronger, but might only be avail. in sizes too wide for TR3.)
Also, I second the point about considering only stainless steel wires, if going for the highly polished look. Most TRs were supplied with silver painted (Argent) wire wheels, but they were offered in chrome and body color paint finishes, too. So, none is any more "original" or "correct" than the other, go with what you like.
Wires are also a little fussier to keep clean, but the extra TLC doesn't really seem to bother most LBC owners.