Thinking about adding a digital temp gauge.
Just drill and tap the hose...that will work won't it?...lol. Make sure you do it when the bike is cool though...lol.
Seriously...
I don't know the size, but it's around 1" or 25mm.
You thinking of installing a tee fitting in the hose?
I'd install it in the big hose on the right hand side of the engine, somewhere convenient between the engine and the rad...this will give you the most accurate temp imho.
Good luck. I'd like to see how this is set up. I think it's a great idea.
Rem