The engine oil thread is like a can of worms for any auto/bike forum.
As for me, using only JASO MA approved oil.
Viscosity like 10W-40,15W-50 depends on your average climate you are and not the engine working temperature.
As for dino or synthetic oil, syth last longer, more expensive and IMHO, shifts better. Changing oil is like changing his/her blood.
However, whatever it is dino/syth, regular interval changing of the oil preserves the cleaniness of the engine. Clean oil is better than dirty oil. Followed by dirty oil is better than no oil. I use syth because the V does really need much oil.
IMO, avoid putting additives. It changes the characteristic of the engine oil. A lot of R&D had been put into the final oil package. Only way to be really satisfied, test one brand each time every oil change. You be the Judge.
What I do after draining my oil is to blow in some air to purge out the dirty oil more. As VeeWNC pointed out about the oil filter, putting oil in the filter before screwing in is good practise. It prevents air locks in the lubrication system.
Warm up your bike ncely before you rev her up. Complete oil circulation and prevention of thermal shock helps a lot to reduce excessive wear and tear.