I run super corsa's on most of my bikes, really like them.
If your running the 3.5" RS front wheel then I would go with the 120 your using now or the 115/120 if you want to run a slick.
The 150 will be perfect for the 4.5" rear wheel unless you have the RS 5.00 or 5.25 which should really run a 160.
Tyre pressure really depends on the day.
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If I have to take the carbs off once more...