Many choices available, and although you can maintain the exact cross section profile for our likable handling traits, the dust will settle on a tyre that will be around 10mm taller +/- at the sidewall. Either raise the front end or go to a 110/18 front to fudge a bit. It's a good trade, IMHO. I get teaser rain for thirty minutes a LOT in my hills and the 110 change gives me that ROSSI syndrome . Either do that or go live in the UK for a while. I've never seen a mass group of biker blokes that can ride as well in the rain as UK bikers. "Rain ? What rain?"
G'day mate, I live in Melbourne Aus, well know for it inconsistent weather, although I still think it's more of a bad reputation than anything else.
I also commute every day in motorcycle, Summer, Autumn, Winter, Spring and the best of all Melbourne-make-up-your-mind, where we can have any/all session in 1 day.
I bet Britons are so used to the rain that having a sunny days is the odd ball hahaha.
For all weather rides I prefer to use my Africa Twin. From commuting in sunny / rainy days for 40km (about 50 min each trip) to go for weekends adventure rides to the hills with whatever the conditions might be, any conditions including rain in clay roads, mud, heavy fog, of dry and dusty and everything in between.
I wouldn't put the interceptor in those situations though, I bought the Interceptor as a nice classic bike what I will prefer to keep clean and shinny (Mark Two, chrome)
The wider tyre is more a cosmetic thing as the original one look a bit skinny.