Just got back from LBJ. The guides make the piles and they know where they are. Otherwise you won't catch anything. We caught 32 keepers and some nice cats. If you want a referral PM me. Really if you try to find them yourself your wasting your time.
with decent sonar and learning what to look for, you can find, mark, fish and return to brushpiles on any lake or body of water on the planet.
Hiring guides , and learning from them is your smartest , cheapest route in the long run if you want to be a successful crappie angler. Crappie can be some of the hardest fish to pattern. Its always a fun challenge.