The only way to get better at avoiding suicide bullets is to practice. The greatest way to do this is to limit yourself to only 1 credit every playthrough, and never hitting continue when you lose all your lives.
If you keep up this strict training regiment, you will soon find yourself getting better and better and making it further in the game without dying. Soon you will be able to dodge like a pro, and those suicide bullets in the gorge level will no longer be a problem for you.
Also, you might want to try playing through a few stages on level 2 or 3. If your only playing at level 1 before hitting gorge, the extreme shift in difficulty may be what's tripping you up.
In short, play with more discipline. You'll be amazed at the results.
Edit: You can also position your familiar in front of you. The familiar eats suicide bullets.