Technique can be different for different people, some can spin where others mash. I think you have to find what works for you. I like to spin to protect my knees, usually seated but stand on and off. I don't use a heart monitor but if it's a long climb I try to take it easy and conserve. I also use a triple, but then I'm old and fat. It might help you if you can warm up 15-20 minutes before the first climb. If you keep at it you will become a good climber but if you want to go fast on the flats you need to do the flats, too.