My CZ .416 Rigby has a 13.5" LOP which is fine for me and is in fact the LOP on all my rifles. I'm 5"10" but thick ( ok, overweight) through the shoulder. Many variables come into determining LOP.

I will only ever use my rifle in warm climes so I can eliminate thickness of clothing such as a warm jacket affecting LOP. Really it comes down to what feels comfortable to you. Close your eyes, mount the rifle and assume an aiming position. Then open your eyes and if it looks right and feels right you are mostly there.

If you are 6' and have long arms 14" will be fine. You may find you just like to be closer to the action ( no pun intended ) then 14" will be too long. If you are going hunting with a thick warm jacket on, you will have to test LOP with that clothing on.

At a guess, 14" and an average build you will be fine.