Is it okay to have all buttons evenly spaced, including the top to second button? Is this okay as long as the spacing is not too wide? Maybe 3" spacing from center to center, for a small size shirt?
Haven't worn Mercer OCBD's in a while but I seem to recall a "too substantial" opening between the top and second button when I wore without a tie. It does make a difference.A 3 inch gap from the top button to the second button would be a bit odd.
On one hand, if the shirt is an OCBD and you intend to wear it with the collar open, it would provide a very substantial, likely too substantial, opening at the collar.
If it's a shirt you intend to wear with a tie, the spacing of the second button would lead to some odd behavior of the fabric lying between the collar button and the second button.