I've seen enough time wasted at the field with plastic spinners that I don't use them at all. On sport planes that don't need a spinner for looks, an aluminum spinner nut puts an end to the problem You can use your regular engine prop washer and nut, and the use the spinner nut as a jamb nut. Works great. Here are some examples:
http://www2.towerhobbies.com/cgi-bin...?&I=LXK241&P=C
http://www2.towerhobbies.com/cgi-bin...?&I=LXE159&P=C
Larry