Whatever it takes to get the sound out for a particular song or instrumental is right. Shame on your teachers for being so opinionated. I've used both in any and all circumstances. Feel that fingerpicks, though unwieldy at the beginning give one more dynamic range onstage. The countless hours I spent forcing myself to re-learn w/fingerpicks things I already knew were well worth it. I 'have' recorded using them, but feel they can be noisy in those situations. Started out using the Nationals, but found out the Dunlops were much more comfortable. Still prefer the National mediums for the thumb, however. Just can't seem to find them, anymore. How I learned to use fingerpicks was to get the thinnest made (.013 in the Dunlops) and as I got used to them, gradually go to a heavier guage. In my case I maxed out at .020. Another thing is that I always keep three sets going at the same time. It takes awhile to wear the edge off of them. Have tried the plastic ones, but they always seemed a little thick to me and would wear out too quickly on metal strings. Have settled on medium flatpicks as they seem the most versatile. I do a combination of strumming and single note bass runs while singing and the 'flex' in the mediums seems best suited to how I play. Have tried heavier guage flatpicks, but I always felt like I was 'trudging along' instead of driving the rhythm of the song. lol Same with strings. I've settled on mediums as they seem to have the right tension.