1- The R3 is water cooled, so temperature wise there's no reason to go with W40. W30 is more than enough.
If the engine oil also lubricates the clutch, you'll have to go with W40. No other way around, unless it's motorcycle W30.
The first letter really depends on ambient temperature.
If you're in FL, where the weather doesn't drop below 75F, 10W40 is good enough.
If you are living in an area where the temps are just above freezing point, 10W40 may make the bike harder to start, or idle when cold.
You should get 5W40, or 5W30 if it has a dry clutch.
There's no clear guide whether it's better to use thinner oil during engine break in, or not.
But one thing is pretty common, around 25-35k miles you should think of getting heavier oils, like 10W40, and 15w40 around 50k miles, not when it's new.
Lower numbers don't necessarily mean lower oil life, or worse lubrication.
It just means for engines running lower operating temperatures.
It also means better suited for lower free play/ tighter tolerances (Aka newer engines).