Defiantly take the MSF pal, they will teach you everything from the ground up, and since you said you've been riding a 250 already they will probably fix a lot of the stuff you already do wrong.
The biggest thing you'll get out of it though is experience and that leads to confidence, which is what your problem seems to be right now.
You can only get so much out of a book, and w/ the MSF course they are right there in a controlled environment to tell you what you did wrong and what you did right. They go over counter steering, swerving, braking, turn apex's, counter weighting, signaling, and most importantly SAFETY. Just don't ride up on your gixxer and expect them not to give you a hard time about it.