My PB Crappie surrendered to a 1/16 oz Roadrunner on 4# Stren in a deep brush pile. If obstructions are very abrasive you could go 6# but it's a personal preference. I don't use Stren anymore in favor of 4# Vanish. I'm just more comfortable now seeing the line a little better. Any good 4# Fluoro or Mono that fits your budget with quality matching UL equipment is a good choice. No braids and no terminal snaps or swivels. Use slip floats, no springs.
This is really complex
On my B&M poles I use 10# stren yellow to a 0 swivel or a double uni knot and use a 4-6# clear or green Trilene XL.
On spinning stuff I use either a 7.5 ML or a 8.5 L with 6 or 4 trilene clear or green XL.
I use these lines because I have a back up of large spools of them and they work. No need for flouro at this point although I've used sensation and found it worked also. You just want a stealthy leader.
I watch bluegills, rockbass, crappie and green sunfish nearly every day as they move into and through the small bay I live on. I've seen people catch them on towtruck cables and micro-lines. I've watched them stare at a worm or cricket and never bite. I've watched them hit 1/2 oz bass jigs and 10" plastic worms.
I think that shallow water requires about a foot of the lightest line appropriate. I'm not a true believer in spooling up with micro-line. Its a problem waiting to happen on a spinning rod.
For the last few years I experimented with 6# fireline and a 4 foot mono leader. It works ok for 1/8 oz and above but for 1/32 the darn fireline floats and you lose feel.
We're leaving in a couple weeks for our first road trip of the year. We're going to NE arkansas Beaver Lake. That lake is( as I understand it) usually a very clear lake,, which is why we chose it. But it is currently still at flood level so we are expecting at least murky water and a late crappie spawn.
We had picked up a few dozen 1/32 oz lead heads and tied up some nifty hair jigs to use under a small float.
I'll bet we end up tossing roadrunners and 1/8 oz jigs.
DON'T worry,, we also have buckets of Gulp minnows and a well used minnow bucket. Whats the fun of crappie fishing without minnows and a float.
So we'll be doing mostly long poles into the buckbrush and condos and brushpiles. Thats where the 10# comes into use. You only loose a couple of feet of mono and its no problem to rig up and go at um again.