Hybrid Picking--holding a flatpick (between the thumb and first finger) and using one or two other fingers for other strings is the way to go if you can master it! Although I've seen and heard it used I've never explored it but it can be very useful in imparting dynamics to many songs. For regular fingerpicking on a 12-string the usage of thumb and fingerpicks, given the spacing between string courses is pretty much a must.
Thanks Rick this is helpful. I think I just need to practice more. I have a VHS (yes, a VHS!) of Roger McGuinn on the 12 string and he mentions starting with a thumb and fingerpicks and then moving to a flat pick and fingerpicks to be able to easily strum and pick. I am not sure I want to try to learn something that new at this point. Part of the problem may just be that I am playing very late at night with the amp turned way down. Maybe I'll try in the daytime with the volume up and see how it sounds.
Paul, back when I could play, I always finger picked my 12-string. Full transparency, after sixty years of playing guitar, I still can't use a flat pick. I can't hang on to it right, I can't hit the strings right, I just can't do it at all. So I've always finger picked, though if I had to say so, I was pretty good at it. When I did want to or had to strum, I just did it with the thumb and finger picks on. But anyway, when I played, I just picked away at my 12 string and it sounded fine. I don't know how I hit the strings, but I got the right sound out of the guitar. I know this doesn't answer your question but I'm just letting you know my experience
Who plays a 12-string with a thumb pick and finger picks? How do you get the lower of the two paired strings to sound loud enough (thumb) or the higher of the two paired strings to sound loud enough (fingers)? By higher and lower I mean relative to the bottom of the guitar, not in pitch.