what brakes do you want to run?. newer decedents of the Mafac ones..
Empella Froglegs, EuroX copies and such,
have no pad height adjustments, so Where you place the bosses
determines the brake adjustment.

My older forks have a narrow boss spacing,
but the modern cross forks have a wider spacing. [narrower than the rear]
and so the brakes are made to suit the cross/MTB spacing ..

I'd buy the brakes , fit the wheels, and let them tell you what the spacing,
and location, should be..

That's what I did 35 years ago with the Mafac ones..

AlAn cross frames had the bosses on the center line of the fork blade,
no off set, [but they got adhesive bonded not brazed]