With regards to seats, they are:
- Economy: 44cm wide
- Plus: 46,5cm wide
- Business: 58,5-61cm wide (lie-flat, 196-202 cm long)
Some seat info:
https://scandinaviantraveler.com/en/newcabin
By my experience, about 30-40% of flights have seats available for upgrade to Business at check-in. But again, it probably depends quite a lot on route and time of day.