Tell me about arm strength

[Gluesniffer]

So I'm doing some pseudo-Starting Strength program that my gym allows me to do, and I'e decided to add the arm work on Friday, which consists of 2 sets of biceps and two sets of triceps work. Now my gym has got dumbells but no barbells. I'm pretty sure that the best biceps strength movement I can do is alternated DB curl. But what about triceps? For now I am doing rope pulldowns, but I don't know whether they contibute much to strength, maybe there's some DB exercise that will perform better for this goal. Another question I have is what amount of reps I should be aiming at. Thanks in advance.

[Mr I]

lying on your back on a bench hold two dumbells hammer grip so palms facing each other with your arms starting straight up over your head at 90 degrees to your body, then bend at the elbow lowering the dumbells down to your forehead and then back up to straight

[alwaysgrowing]

I like Mr. I exercise. To change up the angle, drop your elbows back until they are above your eye. Then bend at the elbows

[Gluesniffer]

lying on your back on a bench hold two dumbells hammer grip so palms facing each other with your arms starting straight up over your head at 90 degrees to your body, then bend at the elbow lowering the dumbells down to your forehead and then back up to straight

Thanks for the hint. Can you get decent ROM on this excercise? It seems to me like it would be skull crushers minus quite a few degrees.