I want to use 30 - 50 lb braid with a 20 lb flouro leader on a baitcaster reel for fairly clear water crankbaits and plastic craws in the weeds.

How long ( or short?) should the leader(s) be?

And is it really stupid to use a flouro leader if there are pike in the area?

Don't know about pike, I don't have any.  But I use about 6 feet. That way I can retie many times before having to tie on another leader

Any length you like. 18" - 24" is pretty much the standard.

8-)

My rule of thumb is that the leader shouldn't reach the spool when you're about to cast.  Other wise any length you like.

I usually start with 3'-5' because I use 20# fluorocarbon leader for weight to make the superline sink for weighless presentations. I replace it when I retie enought to get down to about 2'.

Having a leader that is long enough to wrap around the reel spool defeats one of the best attributes of superline (no memory).

2 to 5 '....

Pike will cut braid easier than they will fluoro.

I use about 3' of leader.

like most people say , 2'-4' is pretty standard as far as leaders go . as for pike , most big pike hunters use 80 or 100 lb. braid with a 80-130lb flouro carbon leaders , lots of abbrasion resistance !!!