What is the best way to drill a hole in a tower?

So I scored a single tap tower setup for relatively cheap but would rather have a twin tap tower. It looks like my cheapest option is to just add a tap to it by drilling a hole and buying the kit from keg connection.
My only concern is how do I go about drilling this hole. Would a hole saw work best or a step bit perhaps? Is a drill press necessary?

start small and work your way up in size till u get to the diameter of the hole saws center bore.

Mine was made of brass and painted black, so it SUCKED to drill.

I did two holes, one with a hole saw and a drill press. The other I small holes all around the perimeter of the hole I wanted, and then used a dremel to cut the little slivers between the holes.

The dremel way was way faster and easier! And remeber that the hole does not have to be super pretty, because you have a flange that cover about a 1/4" all the way around.

I went the smaller hole - then dremel route myself.

And cover the whole tower with masking tape, so when you start manhandling it you don't mess up the finish.

I used a small hole saw, worked like a charm.

Excellent, I think I will start with a small hole and see how easy the material is to cut and go from there.
The tape is a great idea too....

This may be a little over the top but this is what I did as a test project for a friend.

A friend of mine came over with a wasted brass tower all dented up, egg shaped with the chrome peeling off, that alone is a finger slicer.
I had an idea and machined a 1/8" aluminum washer that had a I.D. large enough to allow for the plasma nozzle to center cutting area distance, added this to the hole diameter. Ran this washer thru a set of slip rollers to match the radius of the tower.
Secured this guide washer to the tower with a "C" clamp a piece of wood inside the tower with a matching radius to prevent a "C" clamp contact mark coming thru the tower. A quick loop against this guide produced a perfect circle within 7 seconds. A minute with a half round file for a bur and slag free hole. A test project that worked off a wild hair idea.
This with a Hypertherm Max 20 plasma cutter that was used but in like new condition that I found in a estate antique funiture store a friend has as his business. I paid $125 for a perfectly operating machine that checked out by my Miller service repair friend, Miller used to repair Hypertherm plasma cutters. I got a lucky find on this machine. Sad part it's rated clean to .200" but can cut .250 not as clean. A Miller 375 would make me happy as it's able to cut clean to .375", cut .500" but not as clean. Add this to my big future wish list of items.