The intensity day can cycle as needed through different rep schemes. I would not do any back off sets on intensity day, as you said you're volume sensitive.
Intensity example:
Week 1: 1x5
Week 2: 2x3
Week 3: 3x2
For volume days try adding a set each week before increasing load.
Week 1: 3x5
Week 2: 4x5
Week 3: 5x5
If you are accumulating to much stress then after the 3 week cycle take a light week to disputes some fatigue and ramp to 1x5 at 80% on both days.