According to the services manual:
Front fork leg oil level a
(from the top of the inner tube,
with the inner tube fully compressed,
and without the fork
110 mm (4.33 in)
Yamaha fork and shock oil 5WT
That's for the stock spring, however, the for the progressive, I believe it's more like 5", it will tell you in the instructions when you get your springs. While the height is important, what's more important is that both for tubes are identical. That said, for me it turned out to be just enough to cover the top of the washer/spacer on top of the spring.
As for oil weight, 5WT is fine, but some people chose to go with 7WT or 10WT if they want a firmer ride.