Ours measures 37 inches wide, our left case is set out 1 inch to get around our spare fuel tank, thus they would only be 36 that they are advertised at.
We are running the Jesse Odysseys on our SE and love them, we ran Pelican 1550s on the DR's, the 31L Pelican 1550 weighs .75 kg heavier the the 41L Jesse locks, mountings and all ready to put on the bike.
The op wanted to know plastic or alloy so I won't worry about softies.
With the Odysseys these cleverly bring the weight in low and close to the centreline and do not stick out like a bus.
Having had several brands and types I am sold on Jesses, I have worked on Zegas after a GS 12 rolled and they were parallelogramed very badly and had split, although we have not binned on our new Jesses I know plenty of others who have in spectacular form and they have stood up far better, NOTHING is crash proof.
Jesses strength come from triangulation and folds and finish wise are powdercoated inside and out, also with the Odysseys you can adjust the postion of the case forward and backward 5 inches so you can play with the weight to suit your rising style or passenger etc.
That is our 2 cents worth, if you are looking to do hard core offroad consider Wolfman, if you are RTWing like us or traveling dirt and pavement with smaller offroad stick with hards.
This is our setup, although on and SE I would be happy to put up pics of any queries.