i've done, in order, the train by doing group rides and races approach, the self coach using friel approach, worked with a coach no powermeter, worked with a coach using power, and self coach using power.
of these, by far, no contest, not even close, the best gains I made as a cyclist came the first year I worked with a coach (this was without power, just HR, PE, and honest feedback). there are obvious disclaimers to my experience given the various stages I was in my development as a cyclist and the metrics for these gains, but my thoughts are that the best investment a cyclist can make toward their development is working with a coach. the things I learned about training cycles, building workout schedules, recovery schedules, etc. are invaluable and I continue to use now.
now, how to find one. I strongly advocate local coach who coaches athletes similar to you, knows the races you'll be competing in, and has open communication lines (in this day and age of email, this should be a no brainer). the place to look is in your local racing scene, find out who folks work with and pay attention to their results. that's how I found the coach I used. it's great to talk strategy with your coach prior to a race and tell him/her (yes, women can be a quality coach too) that you think you should attack on the little hill after the big hill on lap 4 coming out of the gravel section, or whatever the race situation is and have them agree or disagree, etc.
also, a good coach might prefer that you use power because it makes their job alot easier, but any coach worth paying doesnt need it.
fwiw, I think you're thinking your development wisely.