Here is the explanation of what Oil I used and the results of over 300 miles....
Firstly I will be using this oil for no more than 500 mile before I change it:
I have had the problem of not easily being able to select neutral on another bike in the past. This was my Honda Pan-European. After a 3000 mile tour through France I notices that by the time I got back to the Ferry across the English Channel, I found ,as well as a neutral selecting difficulty, selecting first with the engine running would make the bike jolt forward, so much so, I started selecting 1st before starting the engine. Anyway once I got home I checked everything I could regarding the clutch and gears. The Honda dealer was not sure and an enquiry to Honda UK was fruitless. However I did get to speak to one of the dealer service engineers who told me the first thing they do is change the oil. So I bought some recommended Honda oil and filter but was still a bit sceptical. I changed the oil and it almost immediately cured the gear problems. However It only lasted about 2500mile when the problems started to come back. Changed again and cured again. I then decided to have the used oil tested by Miller Oils who's semi synthetic oil I'd started to use. They concluded that there was a breakdown of the viscosity due to fuel ingression. This and with the usual shear effect the gears had on the oil greatly reduced the oil life. So I decided to start to use cheaper oil and change it every 2000 miles. One of best of the cheap oils was Lidls 15w40, it was only £10 for five ltrs. and was a good grade. I didn't get any clutch slip so used it fairly regularly only using a genuine bike oil if going touring. I still own the Pan and haven't suffered any more gear problems after over 30,000 miles.
As for the Tuono, I have bought some fully synthetic Shell Advanced 10W40. However before using it I decided to flush the engine with Lidl 15W40 and as soon as I took the bike for a ride I noticed a difference straight away. Although the oil is mineral, it is the correct grade, API SL, ACEA A3. So I have left it in and, at the time of writing, covered 300 miles with a very slick gearbox, easy to select neutral and without any clutch slip too. I am concerned that this oil will shear down more readily than a fully synthetic so intend to change it after 500 miles.
Here is a youtube after only 60miles using the Lidl oil.
https://youtu.be/XO2ZRSq11Zs