I went with the Rennline 65mm studs and am wondering if I came up short. Maybe it's a belt and suspenders thing, but was always told to try to have a few threads showing when tight. On the rear with 7mm spacers there are perhaps 4 threads showing which is fine:

But in the front with 15mm spacers, it's almost flush:

Worth worrying about or drive-on and be happy? I know all of the threads of the nut are engaged, but it just seems wrong somehow....

 

I can still see stud threads. Drive-on and be happy IMHO.

I hope you used anti-seize on the threads and nut spherical face. I personally found that without anti-seize, consistent torquing was not possible (I'd notice some nuts would require a massively large breaking torque to loosen vs. others)

 

Usually when you get about 60% through a nut, it can reach maximum strength. Anything passed flush is way more than what it needs. As said above, you are god to go.