I am with Kiwi on this one and I've set-up many multistradas for street and track alike. Not only will the rear ride height help the bike steer but it will keep you off the pipe guard down by the cases when you really crank it over.
At your weight I would be careful(which is not to say you don't need it) of adding to much preload to the rear spring because you might be near minimum sag already with your present set-up. What is your rear sag? I'll reread your post in case I missed it. It is also important to remember that more preload, front or rear, will add even more rideheight respectively. Sometimes that is good and sometimes that is bad, but it is important to keep in mind.
I'd also try taking out some compression in the fork, say 1 3/4 to 2 turns from full in. This might allow it to ride lower in the front and keep that skippy feeling from happening. In your case I don't think you are 'getting into' the fork enough to get good feedback and control.
Try 35mm total sag in rear and 40-43mm total sag in front. These are my baseline multistrada numbers and not always the final numbers. Rider preference may dictate variations.
Don't break one of the golden rules of suspension tuning and do more than one change at a time. You might nail it if you do change multiple things but you won't gain as much knowledge, which will help you with future bikes.
and take good notes
more later