Think you may find most early 1000's and most 600/750 until recently run a 5.5. When I researched which would fit my 1000 I had to steer clear of some early gixers
I opted for San Miguel in the end. And a 190/50 rear. The 180 made me nervous because of going off the edge of the tire so much.
With a 55 profile it will be harder to get off the rear Loz and you get more side grip for powering that T9 out of 272 corners on one wheel
As said before make sure the chain is longer, the bike is taller so (what I read) tells me that compensates for a longer wheelbase so no lesser turn in but more edge grip