Bob-

If you are tapping through holes, spiral-point taps are the way to go.
They push the chips ahead of the tap through the hole and are suitable
for machine tapping. The cutting fluid I use when mist or flood
cooling is unavailable is Relton "A-9". "Aluma-Tap" works too!

As far as ER collets, size the holder to the application. For
example, ER16 in MT1, ER25 in MT2, ER32 in R-8; though I did use ER11
for some very small drills in a 10 HP Okuma turret :-)

Regards,
Bob