Last month I had a data analysis project that seemed impossible. I broke it into ten-minute chunks, same principle. Once I started, I couldn't stop and finished the whole section in one sitting. Your method totally works for crushing that initial resistance.
Try setting a timer for just five minutes when you hit that mental block! It tricks your brain into starting because it's such a short commitment. I had a closet door that wouldn't close properly for weeks, and it was just a coat hanger stuck in the track. Once you get past that initial hurdle, the momentum carries you through. Breaking things into tiny steps is the only way I get anything done anymore!
Ever notice how you'll put off a five minute task for weeks? My kitchen drawer was jammed shut for a month because I kept mentally building it into this whole repair ordeal. Finally just yanked it open... took two seconds and was full of old batteries. Now the front door hinge squeaks and I'm doing the same thing all over again.
That "mentally building it into a whole repair ordeal" mindset is a total trap. My buddy avoided a wobbly shelf for ages, thinking it needed anchors, but it just had a loose bracket he tightened in a minute. We somehow convince ourselves small fixes are huge projects until we actually do them.