You might find it easier to use a large adjustable as these generally have a shorter shaft than 40+mm spanners and a better angle on the head. If you have a pit or a lift it will make no difference but you do have to raise the car quite high to get the long spanners in. I have both but always use the adjustable as it's just too difficult raising the car to the height required to use the spanners. Also, you should only need one as the shaft can be locked in gear or park.