If you're still spinning in your desired range, I doubt that yoy're mashing. You're likely using harder gears to climb because you can now. Clipless pedals generally allow you to climb with a bit more power because you can pull up, rather than just push down.
Just focus on keeping your cadence up and spinning at your usual rate and in complete circles. It should become fairly automatic over time. I doubt very much that you either were, or are becoming, a masher. Your knees will complain well before your quads will. Plus, I've seen you pedal; you didn't appear to be mashing. Ride with me again sometime and you'll see the difference. While I'm comfortable riding in a high cadence, I'm just as comfortable on the low end of the spectrum.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher