Editing Spiral Stairs

[Jamie_KMG-365]

Somewhat related to me previous question, I read that Spiral stairs are "fixture symbols", and as such, they do not automatically generate a stairwell.  I also see that they can be resized like a regular symbol, but can they also somehow be modified beyond the two "standard" ones provided (i.e. large and small)?  I have two sets, one inside and one outside, and the inside one wants to turn an additional 540* to the landing above.  Is there any way to show that?  Also, do I just need to manually build a floor as a landing to attach to the spiral stair on the outside one?  I can't see how to do that--a manual roof line, maybe?  Thanks!