All I ever used was a Dremel as well. I find the sanding rolls good for the initial cleanup and knocking off the big casting flaws. I use the ball cutters (mostly #191 and #192) for removing and blending the machining marks around the seats, also to smooth out the spot where the valve guide "bulge" meets the port wall .....
What I use most for smoothing the ports out are Cratex wheels or bits. These are made from grit impregnated rubber and come in all different grits and shapes. I use the plain wheels for most of the port's main walls, cone shaped ones to get into the tighter nooks and crannies .....
You can get a pretty good high polish finish with these, and that's fine for the exhaust port, but for the intake it's better to have a textured finish. This agitates the fuel/air mix a bit as it flows through and keeps the gas droplets from dropping out of it. So, after I smooth and blend the intakes, I go back with a sanding roll and texture them up a bit .....
For me, the big thing is removing and blending all these factory machining and "chatter" marks around the valve seats .....
..... and removing the casting flaws .....
These things are awful from the factory. It looks like the Lunar landscape in there, lol.