You need to bait heavier, every foot step. If you want to do FST. I would also keep the leash much shorter, only give him a couple of feet. I would go back to scent circles, then a circle or box with an X in it, then and E or a B scuffed in. Only bait the letter part of the square or circle. You seem to be progressing a little to fast, especially if IPO tracking is your goal. After you work the scent circles or boxes for a couple of weeks go to serpentines, not straight tracks. But, you need to scuff the track initially, like a set of train tracks. Bait every foot or so and then experiment with placement.
Remember, your dog knows how to track. It has the nose. It is your job to teach the dog to track in the style that you want. The way to teach a dog to track foot step to foot step is in the design of the track and training. Since your dog already knows how to use his nose, you must design tracks that teach the dog how you want it to track. A properly laid track will teach the dog a calm, methodical, accurate style of tracking.
There is no point in rushing the foundation work of tracking, that always comes back to bite you in the ass down the road.
Good luck, tracking is a lot of fun.
“Beware of false knowledge; it is more dangerous than ignorance”. George Bernard Shaw