I've done this before on aftermarket/OEM rims, however not to Rallye rims though. but it's doable IMHO, you'll need a 60 degree countersink to put the seat back in the hole after you drill the lug hole out .625

Chrome lug nuts are available from Gorilla lug nuts in 5/8-18 right or lefthand thread if so desired


Your only issue might be the center cap clearing the hex shank of the 5/8 lug as they are BIG.... but that can easily be rectified as the cap is thin in that area and potmetal