Seems like a little too much air pressure to me.
I'd drop two or three psi both front and rear, if it were me...
On my Nero Corsa, I run 33f/36r most of the time with the Z6 Metzelers.
No problems with wobble...
The Guzzi owners' manual I received with my Nero Corsa recommends 2,2bar front / 2,4bar rear for a solo rider. That equates to 32psi front / 35psi rear...
For two-up, 2,3bar front / 2,5bar rear. That's about 33psi front / 36psi rear...
FWIW, I've gone from the OEM 180/55-17 to a narrower 170/60-17 rear tire and have been pleased with the improved steering response...