The helicopter deal is familiar!, I have a couple bits like that. Dull ferrous bits for everything including aluminum (with some cutting oil or wd40 etc.) and a makita electric grinder full speed all the time-I just lighten the pressure I am putting down on some spots. It takes some time to get used to running an electric wide open and not screw up **** lol (especially controlling the chatter) but for me it's faster and has a better port finish and just works.
As you know I have not ported even close to as many sets as you and some of the other guys have but I have done more than enough to realize it sucks and am not eager to do any more $300 dollar port jobs out of the garage anymore. My best set was a set of amc edelbrock heads and they gave some really good gains with minimal effort plus I dig the amc 360/401 stuff.