I don't pretend to be an expert with slitting saws, but I have used them alot. No matter if it was a 10 dollar Chinese blade or a $70 USA blade they all have runout due to the arbor. I use to fret about it, but I figure its like a a flycutter, you hit and cut and then nothing, repeat, rinse and start over do it some more. I have dialed in arbors, found them to be true put on a name brand USA blade and same deal. As others have said, a half decent blade, reasonable speed and feed that is enough to feel some resistance when hand feeding gives me best results. I use Mist coolant, either fogless or siphon style, they both get the job done. The air in the mist helps clear the chip while the fluid in the mist cools. Flood coolant would be grand but I don't use it on any of machines even though they are ( were) set up for it. The advantage of hand feeding is if things go south, you can pull back instantly and save most of blade teeth, if you are under powerfeed and the wheels come off, usually the blade is toast, if you only loose one or two teeth hand feeding you can still have a usable tool. Usually the problems have been hitting a hard spot in cast iron. My one very spendy USA slitting blade has 3 teeth in a row stripped, it still works fine.