Bro I said all that to be politicaly correct. But honestly I snip them off in broad daylight and place them directly into a cup of water about a 2 second process.Then I move to the scrape spot. Then I dip them.Them they go in the water which gets changed out daily till i get root formation.
It is true about air in the stalk.. I heard it slows down the process. But if ur quick and precise in ur movements i havent had any problems.
I alway wondered my self how to cut underwater. I think that is what people are trying to tell ya when they say cut underwater tho. Maybe the double cut like u described.
Oh yea I also scrape in broad daylight too. Not to make light of the whole process ive done it several times. Being set up to be able to do these things quickly is the key. U dont want to expose ur cuttings to prolonged air so that it would allow air to enter the main stalk.
But yea on another note. Its very easy to clone this way and transplant into the grow medium of ur choice.
The harder i have tried to make things the easier it is the screw my entire grow up.... Growing is so simple man they practicaly grow them selves.