Advancing to Alexxx's state would be like going into a state of serious self delusion. I like to refer to Alexxx as Triple X, the future coming of Arnold, Coleman & Sergio all rolled up in one complete package. The Legend, The Man, The Myth....can I hear a amen!!!
If you look at the function of the forearms/wrist, when doing a hammer curl, you can get a good idea why much more weight can be used in that exercise over a regular DB curl. Remembering that one of the functions of the bicep is to twist the forearms/wrist. If you turn the DB and contract the biceps a bit nearing the top position you will have a more effective arm movement. If you keep the thumps up position at the finisher (top) of the curl it will tend to be less affective for most people.
Another bicep builder that doesn't seem to be done much anymore is the Zotterman curl. Hits the biceps and forearms at a different angle with some respectable results. Good Luck.