My best guess is that you would fit fine in a medium but depending on how long you like your shorts the medium might not be as long as you like. Remember once you put them on that the assos bibs aren't that comfortable standing up, the straps will pull down on your shoulders, but once you are on the bike they are comfortable and designed with that in mind.

Maybe someone here of similar build can help you more but assos shorts are worth trying on. I think you would fit a Large ok but I find shorts that are even a little bit too big to be very uncomfortable on the bike. It is probably true though that with the compression of the assos shorts this is unlikely since you pretty close to both sizes.

If you can try them on an F1 would be worth trying on as well. I liked the mille as I have shorter in height/thighs than you and didn't like the F1 as the bibs seemed better suited to someone longer and thinner of leg so maybe...