I took the opposite tact when I was instructing. I laid it out as solo between 8-13 hours, get your PPL at 40 (well 41 if you count the check ride). I had the syllabus to show what was required, which was a lot, and told them that each hour in the air would require 3-4 hours of self study on each lesson. I told them what I was I looking for in each briefing, and if they couldn’t provide answers during the briefing, we may not fly.
I was demanding but fair and alway available to them. I got my gold seal with an average solo of 11 hours and PPL at 43 hours. The guys who wanted to fly and apply themselves worked hard, those who didn’t I fired as students and told them to go work with the guys that would aim for 80 hour PPL ratings. Most guys would find it was worth it to put up with me being demanding and finish on time than fly with the milkman.
I’d ask prospective instructors why they have trouble getting student through at 40 hours, that will tell you a lot about their quality of instruction.