With some experience, you should be able to run just about anything in your machine. Spend the money and get a TOWA gauge, they come in both the L and M bobbin sizes (L is the smaller and M is the larger bobbins). Its the best money I've spent to help with tension issues. Use it on every bobbin, every time. You can have two bobbins out of the same box and they will work differently. Using the TOWA gauge takes the guesswork out it.
Also, check out the Superior Threads site. Dr. Bob's school of Threadology will help you so much. Here's a short vidoo on tension.
http://www.superiorthreads.com/videos/5-tension/
You can also watch their schedule for a class near you. Usually they are at major quilt shows. Well worth the trip for that class alone! There are classes coming up in Hawaii...I wonder if I can talk DH into a trip.....