My first question would be to ask why you would possibly need a capacity that great?! If I read correctly, you are planning to affix a pair of 41L AND 32L bags to your bike, meaning 41+41+32+32?!?!
I hope I am mistaken in that assumption because that is a lot of storage! 146 LITERS! My Ortliebs come in at about half that and I sometimes cannot manage to fill them without adding unnecessary items.

I cannot see why you would need that much room and cannot imagine any safe way to mount them without severely hurting your handling and/or causing foot strike issues.

If I am mistaken and one pair is 41L and the other is 32L, then those aren't that large and are comparative to the size of my Ortliebs....but the fact that you say yours are twice the size of normal panniers leads me right back to my first point...