It's a function of the age. Just adjust your training to 72-hour intervals. And investigate testosterone supplementation.
No, just stick with the standard increase interval. Remember your first question?-My whole posterior chain, while a lot better than it was, is still far weaker than my upper body strength (I bench more than I deadlift right now, although I haven't really pushed the limit on the deadlift). Blame a decade of desk jockey office work.
Would it make sense to do extra deadlift training to rebuild my posterior so it's not such a liability and unbalanced? If so, what should I swap out temporarily?
Cardio of any type will not compliment strength training. You may be able to tolerate it (see your first question again) but it will not aid in strength acquisition, for reasons discussed in PPST2.-I've been using a rowing machine ergometer as my cardio on the thesis that it is a whole body workout, emphasizes many of the same muscles as the core lifts, and thus might build upon the strength training. I also hate the exercise bike and am too heavy to run.
Do you see any problem with rowing machine cario coupled with the core lifts?