Great effort anyway! The "pecks" you were getting were most likely bluegill. It's doubtful that the size of the braid was your problem. Although, I personally use lighter braids than that. I would also not be too concerned about color - until you locate the crappie and the bite goes off.
Of paramount concern, however, is depth & speed control. With the water temps in the mid 60's as you say, the crappie should be transitioning toward the shallows, IF that's where the bait is headed. Find the bait and then experiment with depth & speed control. You will find the crappie. After that, color may become a factor.
Did you mark any decent bait balls? How do you know what you were marking were crappie? It's difficult to determine sometimes. I found that out when using an Aqua-View, in conjunction with my sonar, while bass fishing. Sometimes perch reflect similar characteristics on your sonar. Bluegill and large bait could be what you are looking at on your graph as well. Just a thought.
"A voyage in search of knowledge need never abandon the spirit of adventure."