Short answer
Choose cloth for the places and seasons where you expect to wear these shirts. Ask the tailor about fibre, weight, weave and care for the specific options; a city's name alone does not determine the right cloth.
Two-fold poplins for the boardroom, oxford and royal oxford for texture, linen blends for the Riviera weeks — collars engineered to stand or roll by choice.
March is for the last of the winter weights; September balances the two seasons — a flannel for the city, an unstructured jacket for the Isar and the mountains beyond.
The full cloth books span fresh open weaves through four-season high-twist to winter flannels and cashmere blends. Bring the tailor your calendar; the shortlist comes back two or three cloths wide.
The itinerary is a proposal: months are planned, dates and venues confirmed individually. Final quotations are confirmed in writing before you commit.