Way too much. Having not ridden in a while I quickly checked the oil window after a warmup, bad light in the garage had me thinking it was way low. Filled up a small amount from an old bottle and went riding. Was getting some stuttering which I've often experienced when low on fuel, so I switched to reserve which usually fixes that within a few seconds. Was still stuttering so I get into a service station and fill up the gas tank which was somewhat low. Took another look in the window and again thought I was bone dry for oil. Got a bottle and added some more...
Well, silly me forgot what the oil window actually looks like it had been so long since I've ridden this bike. It wasn't low, it was already high - I never saw the line because the window was filled with oil. I leave the service station and within a block I'm stalled out on the road. End up pushing my bike almost a mile to my destination. Bike wouldn't turn over at this point.
Realizing the error I managed a quick fix to get me home. Not environmentally friendly, but I found a pile of construction dirt/concrete in the parking lot and tipped the bike to get down to the right oil level. Had a 2+ mile ride home which was done slowly along the side of the road, stalling a couple times, smoking out the back like a James Bond film, getting stares from everyone. At one point I had to push it up a hill because I had little to no power. The more I was able to run the engine the better the performance slowly became, at least enough to get me home.
Plan now is to clean the air filter, check air box, check spark plug, drain oil, clean or change oil filter, and add the correct amount of oil.
Maybe yank your plug and blow it off with some carb cleaner to get any excessive oil residue off. Check your gap while your at it. I see, you already had that on your list. Looks like you pretty much got it.