What is an A3?
Here are some good tips for the A3+'s For the V3+'s:I think at that level the best way to progress is just to climb lots of boulder problems in a variety of styles. If you are particularly struggling of overhangs then maybe you are lacking some upper body power and core strength, in which case doing some pull up, push ups and other conditioning exercises probably won't hurt. I don't think you need to consider fingerboarding or campussing at this stage. Also, be careful training at the end of a session when you are already fatigued, as it is easy to injure yourself. If you are struggling to fit in the regime you want to do then prioritise training your main weaknesses. But in my opinion, at this level of climbing, don't skip on climbing sessions to do other types of training as actual climbing will probably yield the greatest improvements.All my own opinion and I am no expert on training so might be complete bollocks.
Well I am no expert either, but I’d agree with him. At V3/4 you probably have lots of strength gains to make by just going climbing on problems you find difficult. Stop before you feel really tired, continuing just means you will do less hard climbing because you will take longer to recover before your next session. So lots of shorter good sessions with good rest is best imoYou probably have lots to gain in technique too. This is trickier, but climbing with technically better climbers and doing some reading round will help. John Kettle has a book on technique drills, Dave Macleod has some interesting books, ask around.
I think you're overthinking it. Just go climbing as much as you can and keep trying problems of lots of different styles. There's no shortcut for time spent climbing and at V3 you'll have loads of improvement to make naturally without thinking of it as training.