I really don't understand why everyone seems to be so hesitant to put fluoro on spinning reels.  I've been fishing with 6 & 10lb seaguar carbon pro (which is generally considerred pretty stiff as far as today's fluoro's go...) on my spinning reels for years now without any more problems than I have with regular mono!! 

3 tips about it though:
1)  Do not try to overfill the reel-spool!  I leave a lip on the spool of about 3/16" minimum.
2)  I do pre-stretch all my fluoro on any reel before I use it.  After I spool up new line, I tie on a bait and hook it to the edge of my garage and then walk off about 30-35 yards of line,...then I give it a good strrrrrrretch (5-10 feet) before I wind it back onto the reel!  There is a very noticable difference in how the line handles before and after doing this!!!
3)  Any time I start noticing much line twist,..I straighten it by dragging the bare line in back of the boat for a bit.