I also have a Tin Lizzie. This link helped me get my tension right. It's a step-by-step.
http://www.quiltingboard.com/main-f1...t-t114933.html
I agree with ckcowl on the pokies on the curve. Even with a stitch regulator you need to make sure that you're not going too fast. My machine is very un fussy about thread, and once I figured out how to set the tension, very little adjustment was needed.
Usually when you have a mass of top thread on the bottom, the top tension is way too low OR the presser foot isn't lowered.