yes 6 pm would be best and yes centre bolt loosened to rotate the adaptor however this is meant to be installed and then not moved as theres two O rings inside. You should get away with a change of position but make sure the filter isnt trapped as its not something to do repeatedly.
I think a shorter filter such as Mann W77 would work (and this has been done by some owners) as the change in pressure drop is minimal until its starts to block up but these days our cars tend to get oil and filters changes long before their mileage dictates...