CTL is only a rough metric for measuring fitness (or better yet, Work Capacity). Where you start your training plan has a great deal with where your CTL will end up.
Keep in mind that these stock plans are by necessity “one size fits all”. They have to be very general because we do not know who will be using them. They are based on the exact same training ideas and plan discussed in our book. The only difference from the book is that we had to make some assumptions and choose a starting volume. We chose a rather conservative volume so as to lessen the chance of doing damage to an unprepared user. Proper training must be highly individualized to meet the needs of the athlete. That is why we have so much free information about training theory and how to individualize your training for yourself both on the site and in the book. As cookie cutter as this plan is, it can be modified to suit your personal fitness level.
If you come into it with very little previous training background then this plan will do as good a job as possible (outside a custom plan or coaching) in getting you ready using the indicated hours. If on the other hand you have a higher level of starting fitness then you’d be wise to use a higher volume. The plan’s structure will be the same just the volume of aerobic work will change.
This plan has been used quite successfully for substantial undertakings on 8000m peaks and other. Please read this:https://uphillathlete.com/cassin-training/
Good Luck with your goals