Wheel Stud question

[PaulDash]

So... about to replace brake discs and was thinking of mounting wheel studs instead of using bolts. Need help determining correct length.

The rear wheels already have factory 17mm spacers as car originally came with option 413: 18" Turbo look wheels. Those spacers already have studs in them so it makes sense to have them up front as well. Front wheels will have 5mm spacers mounted for aesthetics.

What length studs to I need?

Also, do I need screw-in studs like these: Competition Wheel Studs (ea) or will the hub accept the press-in type?