If you have lots of tubes to notch, then the hole saw set up is ideal. Before these came out, I had built complete race cars using nothing more than a sawzall to get close and (2) 4" Makita grinders, one with a thin grinding disc and 1 with a wider coarse grinding disc. Once the majority of the material is cut away with the saw, use the coarse disc to get the shape close then use the thin disc to finish the fit. It takes a little practice but once you do a couple, you will be surprised at how fast you can cope tubes with the hand grinders...and we built several off road race cars with this method.