I've made a custom set, bought several more over the years too. But if you're going to all that trouble, your efforts should be superior to what you can buy commercially, not done in an effort to save a buck or two.
First off, I'm from the land of no wind. Many of my fellow local pilots (and myself included!) prefer a handle much longer than people on the coast-line would ever consider "normal". When I wanted a custom set for my needs I arranged for 3/8 inch diameter titanium tubes, about 19 inches long. I bent them with a pipe bender, but almost all of the bending angle is very high on the grip, towards the top.
Lots of the time you'll see two bend angles with your hand (grasping position) in between these bends. For my style, I prefer all the angle up high and gradually straightening out as it gets towards the bottom attachment point. The french guys (Crazy Drivers) use handles that I would consider inverted,.... all the bendy part in on their bottom part of the handle!
There's no one correct answer, you may want it completely different and that's the cool part about quad-lined kites, Revs in particular. You decide what is correct for you, nobody else's opinion really matters.
My titanium handles are lighter in weight with a set of 120s wound-around them than the stock pro handles without any lines at all! Of course you don't need anything like these to enjoy a afternoon of flying fun. My Ti handles have been run over by a police squad car on the mall grounds without any damage, so that light weight doesn't equate to a weakness in strength. Long throws with little mass means you can have a profound impact on the kite end with the tiniest thumb flick from the pilot's end, so older folks, like me!,.... can still flail with the youngsters.