There are some good tips here: shorter rusting period, finer polish and 'express' or hot application. But also higher carding wheel speed will add to the luster, with a very light touch. (I use as hot a mix as possible so I can get in 3-5 coats per day, 2 hours in the box max after warm-up.)
I use a slow speed for the first couple of coats, then increase rpm's after I have a good base coats.
Anyone can turn gun metal blue/black. Getting a really superior deeply colored finish without a matte surface is the achievement. There are a hundred tips, techniques and anomolies if you've been doing it a couple of decades.
Best,
Steve
