Thats varnishing not glazing.
Glazing is the process of adding thin layers of paint.
To varnish the paint needs to be completely dry, I read that it was a minimum of 6 months.
Thats the first time Ive heard anybody say you could do it within a month.

No just wait til the paint is touch-dry.
People love to be esoteric and complicated about very simple things.

How strange, I assumed you must have been talking about varnishing because of the years wait.
It would take an awfully long time to finish a painting if one waited a year between each glaze!

Yes fat over lean!

If the underpainting is dry and not too thick and if it’s medium is fairly oil free, then proceed with caution. Each successive layer needs to be a bit more oily than the lower one.

If the under paint is a thick oily impasto, then you can have problems with a dryer glaze skinning over and preventing the thick impasto paint from drying out.

There is a story of a large oil painting which has to be turned upside down every year to allow the thick paint to flow the other way.

Varnishing has similar issues, and you do have to wait until the painting is dry before you varnish.

Some professional oil artists will use a retouch varnish sooner as it will breathe.

I have read many articles on glazing online and also watched numerous videos. There seem to be two different techniques being called by the same name.

1. Glazing 1 – Painting thinly in layers into a couch made of medium, where the medium should be something less than 30% of the total mixture of paint and medium.

2. Glazing 2 – A very thin layer of paint-medium mixture where the paint is very visibly diluted by the medium. In this case, the medium would constitute a large portion of the mixture. This is explained and demonstrated in one video as such:

https://www.youtube.com/watch?v=s7PJ52L4H7E
It’s not the best video on this glazing-in-the-end technique, but it makes the point.

There is also this article on glazing:
http://www.essentialvermeer.com/technique/technique_glazing.html

It states that “Modern art historian are apt to abuse the term and describe any layer of paint that is not completely opaque as a glaze.”

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Personally, I make use of both methods to produce different effects. Method 1 helps me build up my layers and method 2 allows me to play with shifting hues.
Shrinkage in oil painting layers in an observable phenomenon and I am convinced that allowing time for shrinkage will result in a long-lasting painting.

My wait time between layers continues to be a month or more. I never care about fat over lean.