Mary had some good advice up top too. here are my rules for rigging changes:

1) Even if the changes you are planning are proven on other boats NEVER, EVER, make more than 2 rigging changes between sailing sessions.

2) if you are trying something that is unproven (if #3 doesn't apply), NEVER, EVER make more than 1 rigging change between sailing sessions.

3) look at other boats - if you like the way something looks, talk to the owner how to make sure they are happy with it before you steal the idea.

4) whenever possible, temporarily mount things to prove out the positions using line or other mounting points to avoid drilling extra holes....I hate extra holes or having to remake rigging that I messed up.

5) Bounce ideas off your crew whenever possible. It helps them feel like you care (even if you don't)

6) Crew the boat occasionally to see what hell you have unleashed on that person by the latest change.

These rules have done me pretty well on the F18 and although we've been tweaking the boat for 6 months, we've got some pretty fancy yet simple and streamlined rigging, are almost rigged how we like it, and haven't had to undo anything we've added.