There is more than one way to skin a cat. Different locations require different techniques. Bottom line is something that will acttract crappie. Location is probably at least as important as what you use to make it with. And there are lots of different ideas on where to put brushpiles.
On Cedar Cree Lake in E Tx, I tried to put my brushpiles in 20' of water. That means if the lake was 5' low, I'd put it at 15' according to my depth finder. So, when the lake was full, I'd be at 20' to the bottom of the pile. Since the pile typically was at least 5' tall, I would have 15' to the top of the pile when at full pool. A pretty good depth or late spring and most of the summer.
Would also try to find the top of a drop off or close to it.
And, always dropped most for protection from southerly winds with few protecting from northerly winds. This way you could usually find one with some wind protection.
Just a lot of things to consider when putting out brush.