Now that I think about it, I have enough grade 8 studs to do most of the holes since I bought a set that was way too long at first. I may just throw those on in hopes of getting a decent seal. I think the stock hardware had some kind of special nut to center the studs on the ends in their hole. Not sure how necessary that'll for something like this.
yea, I wouldn't be concerned with those for now either - hell, I have used washers to make up space when the bolt has been too long. You're not looking for pretty at this point - just function.