How Much Oil In Sump?

Does anyone know how much oil, when drained out of the small front plug, would have been a concern (Main Seal) if the bike had been started without draining?
I had a bit of a look but couldn't find anything.
Cheers

I have started my Commando with most of the oil tank drained into the sump, without issue.
The bike has the Comstock/CNW sump vent which is supposed to help evacuate oil from the sump.
Some folks have started their bikes with excess oil in the sump, the main seal has blown out, and the oil ended up in the primary case.

I don't think there is no one answer as to how much oil in the sump is too much to start the bike.
Other than the precautionary approach which is to check the oil tank and if the oil level seems low, drain the sump.

It will depend more on the state of the oil seal than how much oil is in the sump.

Put a 1/16" thick viton oring between the sprocket and main oil seal and forget about it. Its only a dollar and then there's no worries. Never had an oil seal blow out in 40 years. And yes - also put in the sump reed valve breather for quicker sump evacuation.