I find the whole setup with the lugs, original strap and original case to be rather awkward. One can't completely remove the case without removing completely removing the strap, so you end up with the case hanging from the strap while you're taking a picture.
A wrist strap ends up on the wrong side of the camera for me and needs to be rather loose so you can change the aperture and focus with your left hand (while it's through the strap). Plus it needs to be pretty thin so it will go through the lug hole in the case.
While the original strap is of a plastic material, it is well made and durable. Before I found an original strap, I tried to use a leather strap from an old lense case, but it was a little too thick and made removing the back of the camera difficult, since the lugs need to slide on the strap to remove the back.
I also tried to use a strap that connected to each lug, but found that it was difficult to get the case on and off over the lugs with the strap ends attached.
I'm afraid I'm not giving you any great ideas. At this point I'm using the original strap and the original case the way they were intended to be used. I't kind of awkward, but the positive side is that it would be very difficult to lose the case.