I’ve asked a lot of questions over the years when it comes to crappie fishing. Regarding line size, guys I trust like Kevin Rogers use straight braid while other accomplished crappie anglers swear by 4-pound fluorocarbon, while still others will say 8-pound monofilament is all you need.
What they all agree on, if you put the jig right on the fish make it move in a way that gets him to react, the line choice becomes irrelevant. What is more important is that you can hold your lure at the level and speed, which is often sitting perfectly still just above the fish, that the crappie prefer.
Your electronics will show you the fish are there, but if you can’t master keeping your distance, holding your boat still so you can work a jig right over the fish, you will struggle to catch big crappie consistently.
I have been practicing with Livescope a lot. By practicing I mean adjusting my range and gain and then focusing on how far away I need to be from the fish to present my lure and then trying to keep the boat in position the whole time regardless of wind or current that may be complicating keeping still.