Gymnastic body : introduction to static strength

In my first post I said I was not using insanity for strength building, but rather inspiration from a book I found by chance : "building the gymnastic body" You can use your favorite search engine to find more about that. here is the graph I've made for the static strength progression in the book.

Static strength progression

According to the advices found in the book here is how it works :
-For each progression you check wich move you are capable of.
-For this move check how long you can keep the position.
-Divide this number by two this is how long is a rep, divide 60 by the rep time and you have your number of rep in a set.
-Add between 45 to 90 seconds of rest between reps.

Ok now an exemple: Say you can do an L-sit for 20 seconds, now your rep time is 10 seconds (20/2) and your number of rep is 6 (60/10). I try to get rest time as short as possible for reps of 5 second I consider 45 sec and for 10 secs reps I use 50. So for this exemple I would do:
 10 / 50 * 6. a total of 6 minutes rest included.

Now that this is understood 2 more things:
-XR and PB stands for Rings (gymnastic rings) and parallel bars.
-For Static work you can usually use paralleletes or pushup bars instead of parallel bars, and a set of ring with straps attached to a pull-up bar can work instead of  real rings.

Ok so now that we have the starting point, how do I go through to that last awesome move in the graph?
I can't really tell you cause I'm not there yet (far from it actually) but this is what I intend to do (following the advices of the coach in the book):
-Keep the same training level for 8 to 12 weeks (The first weeks should be challenging and the last weeks should feel quite easy). The reason is that you need time to improve by challenging yourself, but also time for your muscle to repair itself, well the explaination is better in the book but in short it avoids overtraining and training injuries.
-When your rep is higher than 15 seconds it means you need to level up the exercice
-If you should level up the exercice but can't perform the new exercice, continue with the easier version while experimenting with the new version until you can do the new version.