Hey Todd,
I cut a ton of brass.
Go to a tooling shop (or online) and get bits made for machinining non-ferrous metal. They have a slightly different geometry than the wood bits we are all familiar with. I use Niagra Cutter 1/8" bits by the pack. Luckily they only run about $6 a pop.
I use a PC router and I run it @ 13k rpm, feed .03 -.05 ips, plunge .01 ips. The key is to ramp into every, and i mean every, cut.
My regular pass depths are .02 even for the thicker material I usualy cut, so I think you could do this in one go. Again, ramp into all cuts.
I use CRC thread cutting lubricant. It is nice viscous stuff in a spray can so you can just spray it on the sheet and go. No circulation needed. It does definately help. Cutting dry works, but eats bits and edge quality can suffer.
my only other tip is that tabs can be your best friend for hold down. Brass can be cut down to tabs of .005 -.01 deep (almost like foil) and .125 long depending your Z being accurate. They hold even tiny pieces in place and can be cut out with a utility knife.
Good luck,
and let us know how you do.
Chris
Do not follow where the path may lead. Go instead where there is no path and leave a trail.