FMAK is pretty awesome, and it works alright, but I guess a lot of small segments are a pain.
Actually the profile should run perpendicular to path. FMAK is probably an OK fake in such a case. Extrude edges by rails is more accurate. When I did it it looked good, and the profile was the correct cross section as it continues up the stairs.
[EDIT: I made two paths based on two planes. There was a minute misalignment with the stair wall, which was fixable, and may be due to operator error, making the paths.]
[image: fVbu_Screenshot2012-11-13at2.26.23PM.png]
In the end. what do you use? A Flexi-molding which is of course not geometrically perfect either.