Your guitar looks good, so should your strap. Aesthetics, comfort, and durability are the focus for these straps. A heavyweight leather of 3.5-4mm thickness bound together with strong stitching and rivets ensures a very robust build.
Everyone plays in their own way and so all straps are made to your required length. The best way to choose a length is to lay flat a current guitar strap adjusted to the length you prefer. Then take a tape measure and measure the distance between the button holes at either end (see diagram below).
Measure from the centre of one hole to the centre of the other. If you do not have a guitar strap to hand, get someone to help you by running a tape measure from one strap button, over your shoulder, to the other button while you hold your guitar at the height you prefer. Both ends of the strap offer some adjustment so that you can fine tune your setup to get it just right.
Due to size differences in strap buttons across instruments, getting a secure fit from a guitar strap can be tricky and so both ends of the strap can be rotated to offer a different sized hole (9 mm and 12 mm), which will help you find the most secure fit for your guitar.