If your are not utilysing SD's then your are not doing HST. You are basically doing a short linear periodized routine. If that works well for you then good
. But SD's are a fundamental part of what makes HST "HST".
Without it the huge drop in intensity you were talking about would mean a very infeffecient way to progress. The way HST is meant is hypertrophy without strength. I suggest if you want to continue with HST you re-read or read more indepth so that you understand the theory behind the SD. IMO, the whole thing is silly and overcomplicated.
If you want 'harder muscles' once the fat has diminished you want to concentrate on low reps and stength. This results in increased nerual tone, denser and more functional muscle mass, and thus a "harder" feel and look.
You have actually two differnet goals here the way I see it. You say you want endurance resistance training. But that won't result in the hardest most toned muscle.