Just checking if ROG’s answer has put all your concerns to rest?
Your 1st point you seem to be considering other work as using up your driving time? Is that what you thought? This is not the case.
Your 2nd point, every time this question is raised on here the answer is always the same, that the 2 systems are not added together.
So you would easily work 2 per 8 or even 2 then 3 days per 16 days.