The term ‘sweet spot’ comes from the idea that it’s the best of both worlds in terms of maximizing productivity vs recovery time. So, based on that school of thought, sweet spot work is unique in that you should be able to do more sessions because you’re not getting as fatigued as you would with other high-intensity work. SSBHV throws a bunch at you, but you don’t have v02 work or over unders, so again kind of a unique case.
However, without knowing your prior experience, I wouldn’t jack up the volume after your first training block- completing that one successfully and seeing gains is a sign that you’re already at a good volume for you. If you don’t think you can complete a high volume plan- don’t, and there’s certainly no obligation to. More isn’t necessarily better, and HV is too much for many people!