Stupid notch question. Crooked or straight?

[j.rigby15r]

I need a step notch for my 64 long fleet. I am/was planning on building one myself. However I have ran into a conundrum. Some notches are straight and some are crooked. I know that the 64 frame narrows after the axle. Which makes me think that I have to use the crooked one. But there are a lot more out there that say they will work on my truck that are straight. If I can use a straight one then I will build my own or have it manufactured locally as I live in Alaska and a lot of places want 2-400 just in shipping. Or dose someone have plans or specs on a crooked that I can use? Thanks for your insight.