It's pointless over-complicating any of this shit. If you get a chance to ride at tempo (or race) once or twice a week on top an endurance ride, your bike fitness will fucking soar compared to any amount of systematic longterm turbo work. Thankfully this is the kind of thing that tends to happen in springtime as road conditions improve, you get to feel sprightly during the summer, and then you retract back to a comfortable endurance state over the winter. Repeat ad nauseum. The turbo is a fitness tool which can grab you short term quick burning / quick fading gains in a relatively brief and unpleasant space of time, or a tokenistic calorie burner, or occasional ride replacement option (where 'ride' only equals excitation of heart, lungs and legs rather than anything holistic).
/thread