This is pieced together from the early Layer Days on the Livespill...
HDL (HEAVY DENSITY LIFTING) LAYER
This is the most effective way to stimulate as many fibers to grow as possible, especially now that the nervous system is "on". The HDL layer is a form of strength-endurance, thus based on strength, it is different physical quality and is not 100% proportional. It is a form of training that we have very little experience with and is a function not only of strength but also lactate threshold and lactate clearance rate. as those two improve you become able to perform HDL with a greater percentage of your 1RM.
For loading you start with 65-70% of the ramped max in the first layer (ideally you would eventually be able to use 80-85%). Perform three (3) sets of any one of the following rep schemes.
If your total cluster reps (total for all three sets) was 16 reps or less then you will perform all three HDL sets as follows: 5-4-3-2-1 that is 5 reps/rest 10-15 sec/4 reps/rest 10-15 sec/3 reps/rest 10-15 sec/2 reps/rest 10-15 sec/1 rep/finshed first set... now, if you were able to get more than 17 total cluster reps, instead of 5-4-3-2-1 you will do 4-4-3-3-2-2-1-1 for three sets... Why? Well if you were able to do more than a total of 17 cluster reps with 90% it means that your level of resiliency is very high for your level of strength and thus 5-4-3-2-1 HDL with 65-70% of your max should be too easy... 4-4-3-3-2-2-1-1 requires A LOT more resiliency than 5-4-3-2-1.
Missing the target reps of a rep group... for example you sometimes will get 5-4-3-2-1 on the first set... then the no. 4 rep group will be impossible for the next set and it will look like 5-3-2-1... you may compensate by performing an extra singles or doubles at the end to make up for the missed reps but in most cases I say not to compensate by adding a single or a double... just do what you can for that workout and strive to improve the next time. Never purposely repeat a high rep number micro set only repeat a micro set if it is two or less reps; e.g. if you fail to reach five reps on the first rep group (micro set) never do 4-4-3-2-1 but instead do 4-3-2-2-2-1-1... or 4-3-2-1-1-1-1-1-1... or simply just stop at 4-3-2-1 which is what I would recommend most of the time. *
If at 65% loading and you are unable to complete a single HDL Layer Set (e.g. 5-2-MISS; MISS 5->3-1-1-1)... the solution is to lengthen the rest between micro sets/number rep groups (20 sec, 25 sec.... even 30 seconds if necessary) and gradually work your way down in rest time to 10-15 seconds or less.