Hello Dave,
The secret is to use a really heavy feed, the tooling isn't critical, I have machined nylon with tipped tools, brazed carbide and HSS with equally good results.
Reducing 32 mm stock to 20 mm can be done in two passes, a 4mm roughing cut followed with a 2 mm finishing cut. Work speed is about 500-600 rpm and the 'swarf' justs flows over the tool in a satisfying ribbon.
Coolant for deep drilling, where the risk of hole closure around the drill is present seems to favour WD40 or a paraffin based liquid. For drilling keep pulling out the drill to clear the flutes and when it starts to smoke let things cool down a bit..
Trying to shave off the final thou or so doesn't work well as the stuff is fibrous and just tears.
I hope that helps
Brian