Forgive me if this has been discussed before...
But i have two local mechanics that both gave me a thumbs up on my tire choice (Battleaxe BT45) but they have different opinions on sizing.

One says go with a 110 rear and and a 100/80 front.
The other says 120 rear and 100/90 front.

I've always thought that wider would be better (more surface contact) but it seems that many 'purists' say that the bike was designed with the thinner tires in mind and they are better for our old airheads.

I'd love to know if skinny is actually better and why? Or is it just a matter of opinion?

The bike is going to be a dry street only, cafe style R75/5. The bike is currently being built but it is time to mount some rubber on the rims. I'll want tires that will compliment the cafe/street fighter/ canyon carver riding style.

I have the wider sets on my current bikes but I don't know any different.