I get all my shirts from Hong Kong. I do fitting when in town and then they have the precise measurements however you can do this yourself.
From there all you do is tell them what you want including the quality of the shirting you require. I get French cuffs for most but like to have a variety of looks available. They will also make any jacket you need to any design and fabric.
They are usually cheaper thatn off the rack shirts of the same quality.
I can suggest a reliable and reasonably priced tailor if that helps.