I first started making pens (and pencils) about 15 years ago and all I had was a SS. It's been so long ago I don't even remember the details. I eventually got so enthused with small turnings that I bought a mini-lathe, but I doubt that my results on it were any better. No advice; everyone else has it covered and are much more recent than I am, having not turned a pen in about 10 years (life got in the way of woodworking, and I hate it when that happens!).
'55 Greenie #292284 (Mar-55), '89 SS 510 #020989, Mark VII #408551 (sold 10/14/12), SS Band Saw, (SS 500 #36063 (May-79) now gone to son-in-law as of 11-11), Magna bandsaw, Magna jointer 16185 (May-54), Magna belt sander SS28712 (Dec-82), Magna jigsaw SS4397 (Dec-78), SS biscuit joiner, Zyliss (knockoff) vise, 20+ hand planes, 60s Craftsman tablesaw, CarbaTec mini-lathe, and the usual pile of tools. Hermit of the Hills Woodworks, a hillbilly in the foothills of the Ozarks, scraping by.