In reply to zimpara:
I would have periods training all of these throughout the year, prioritising one and then maintaining the others.
Personally, I start with 3 months of Aerocap (similar protocal to what you described, around 3 sessions a week).
This is followed by PE and Strength training.
If you are after increasing your actual contact strength or targeting a grip you're weak at maximum hangs for between 5 and 10 seconds seem to be the consensus amongst many coaches.
However I'd only recommend these maximum hangs if you are already an experienced climber who's operating in the french 7s or if you have a weak grip to work on (say fully openhanded 3 finger grip).
Bouldering is where it's at for pure strength/power gains.