I would not try and lower the frames. The cases can be lowered by max 20mm by drilling them higher, but as for handling I don't think its going to make a significant difference. On the other hand higher gives you more clearance.

Have not tried them with weight yet but having compared the position to the MM panniers, the Caribou cases are slightly more central and lower on the bike so they should carry the weight better or just as well as MM.

The good thing about using them off road is that if you have a base and want to go off road for the day the frames come off in a minute..

Having had a closer look at the fitting of the frame the left side fits perfectly but the right side is not perfect. I suspect this is one of the frame struts not having been welded on straight. I am speaking to SW to see if this is a design or manufacture issue.

I will let you know