While practicing applying finish if still getting too much build up on the thread, try letting the finish set for a few minutes followed by carefully removing with Acetone. The idea is to remove the excess while allowing enough finish to remain in the thread to seal it, while not disturbing the wrap.
The second coat should be a thin coat to cover the thread leaving a flat, smooth finish. After awhile you will get the feel of applying the first coat and won't have to remove part of it. This worked for me during my learning period, consider it nothing more than a suggestion. You won't go wrong following the advice of Dan or Em. Good luck & enjoy the building experience.