Transmission oil

Best way to change oil is to heat the motor to operating temperature, remove the drain plug and leave standing for 30 mins for all the oil to drain.

Replace the drain plug and fill with 650ml, no more, no less of oil of your choice.

Good choices of oil are: 10w 30 motor oil, no friction modifiers.

Automatic transmission fluid type F.

Motorcycle gear oil designed for wet clutches, there are a few very good brands, the choice is up to you.
 
•Provides more durable anti-wear additives which remain in the oil longer for outstanding protection against friction and wear.

On reading this statement I doubt it would be suitable for wet clutches, I would steer clear.
 
Let's say a blaster has been sitting for 7 years and needed an oil change before it was parked and a rebuild is on its way. Should the bike be started after the rebuild and drained or should I drain it now?
 
Do the 3 to 5 heat cycles, then take the bike for a little ride to warm up the transmission as the tranny has to be hot to allow the oil to run out.

Leave the plug out for at least 30 mins to allow all the oil to drain, replace the drain plug and fill with 650ml, no more, no less of the oil of your choice.