LOUISVILLE, Ky. — Todd Pletcher, trainer of Kentucky Derby favorite Renegade , was on a plane to Louisville when he learned his colt drew the dreaded No. 1 starting post. “I reached for the air sickness bag,” Pletcher said, a good line for one of the more serious trainers in the sport. Drawing the No. 1 hole in the Derby might not be the stroke of doom it was before Churchill Downs went to a single, 20-horse gate, creating a little more room to maneuver into the first straightaway. But still: It’s the easiest place to find traffic trouble, and the last horse to win the race from that post was Ferdinand 40 years ago. Thus, I’m tossing the favorite from my $100 betting plan. What looked like a wide-open race before the post-position draw is even more uncertain now. With that in mind, feel free to take your wagers wherever you have conviction.…