re: OT workout tips for bicep?

With dumbells you should go down in weight. Maybe to the 30-35 range and focus on correct form with higher reps-- 10 to 12 a set. Try and rotate your hand at the top so your pinkie rolls to the top. That's what Arnold attributed to the "peaks" in his biceps.

For straight mass, use a barbell. If you're going to do heavy weights it's OK to cheat on the last set or two.

As another poster said. Work on the triceps just as much, as that will increase the overall size of the upper arm.