I agree with the others. You have the skills. You can do this.
The ruler I like for 60 degree triangles is the Clearview Super60.
https://www.amazon.com/Clearview-Tri...85954417&psc=1
But 60 degree rulers are not all marked the same way, so I would look through the pattern before buying one. Some of them have markings that measure distance from tip to base; others measure along the side. Some have blunt tips, others sharp points. The sharp points are more helpful when doing a OBW.