If you don't want your lugs/studs to stick out past the wheel then something standard like H&R or the basic stud conversion from Motorsport hardware would be your best bet.
If you know you're always going to run a 10mm spacer in the rear, or you're going to run open end lug nuts so that without a spacer the stud can pass through the lug nut, you should probably go with the longer 60mm overall studs.
Conversion stud length needs to take into account how much threads into the hub (typically 12-14mm), then how much of the stud is used from brake rotor thickness, and then wheel thickness. Whatever stud sticks out from the wheel (from the base of where the lug seats) needs to be 14mm+, at least for the minimum thread engagement that is recommended. That should be engagement equal to the width of the stud, as a minimum. More engagement is fine, less can strain too few threads and cause stud failures.
With bolts, the threaded length is what you want to pay attention to, measured from the bottom of the bolt seat to the end of the bolt. The math on that length is the same as the stud, just in reverse. You need to pass through the wheel, brake disc, and then engage ~14mm of bolt threads in the hub (or around 9 turns). If you add a spacer, you have to add that same length to the threaded portion of the bolt. So an OEM length lug bolt is 27mm threaded length, with a 10mm spacer you'd want technically a 37mm bolt, but 40mm is likely going to be the closest you get. Overall bolt lengths are not important in this measuring, because every bolt manufacturer can be different in design for their bolts above the seat (taller hex, taller seat area, etc.).
Gorilla has always sized bolts with both metric and standard dimensions because not everyone is familiar with the metric system, even though lug bolt vehicles are entirely from countries that use the metric system. I agree it looks strange, and it might not be that way in the future