On the topic of FTP. Say I wanted to do an FTP test. I would be doing it on a trainer so I can keep a constant effort for one hour (or twenty minutes, or eight, or whatever the method you're using calls for). How would I know what power output to aim for? Say I feel good at a certain output after 10 minutes, how would I know that is the max effort I can sustain, or that I would not blow up too soon?