Its never a bad thing starting too light. You could go as light as 80% to be honest.
Jim might have another suggestion, but I'm guessing 25-50 reps from each category (push/pull/single leg or core), each workout. It doesn't matter what you use.. KB, DB, w/e... just get the reps in from each category.
Although not the best substitute for standing OHP, you could do seated OHP or incline bench press.
If I were you (I'm 39 years old) and wanted to condition as often as you do while doing a 2x week program, I'd do this:
2 cycles of:
5x5 FSL (can be same as main exercise or the opposite)
25-50 from each category
1 cycle of
5x5 FSL upper, 3-5x5 lower
25-50 from each category, but cut out the single leg work
no need to deload since you're lifting only twice a week.