[Urbane Guerrilla]

If sport jackets are ever allowed, go Harris Tweed. It will last you about the rest of your life. English cuts are also suited to your body type. For Italian suiting you need to be built like a slender Italian guy.

Personally, I would not hesitate to buy navy-blue. Even a rather inexpensive/discounted suit off the peg will hang well if you also budget for a bit of tailoring so it rides well on you and harmonizes with your proportions.

The main thing with wool is what weight. Light or tropical weight wool for hot summers, something thicker for wintry weather. For the classic taste, you can't go wrong with a blue blazer, single breasted in your case, and dark gray slacks. Lighter gray for a lighter look overall.

Don't bother with any tie fabric other than silk. Be picky about where you get your ties from; there will be a ton of quite silky ties out there that just aren't quite right -- either you wonder what they were thinking when they picked those colors or the pattern frankly bores you stiff. But you'll know when you see the right one! Get ties that appeal to your color taste, so they will actually be enjoyable to wear. I've had rather more joy from foulard prints and tartans than rep stripes.