Get the horse first, worry about the cart after. Get the headset figured out AFTER, as they say above.

1-You don't know how much the crown race you choose will take up above the fork crown. That race can vary in thickness, (generally not much.)
2-The headset cups will raise the bearings above and below the head tube.
3-Per your info, you have 40mm to fill with the crown race, bottom bearings/cup and top bearings/cup.

My initial guess is you'll need a spacer, and I suggest making sure you have a keyed spacer (or two) on hand, and maybe a couple 2mm 1" spacers.
In a best case scenario, you simply buy a standard headset and it all works. Often does.