Labia minora, inner lips, can not be made too small/thin during the first major GCS procedure due to issues with blood supply.
In my case and with my doctor about 80% of patients are fine with their first results i.e. only ~ 20% come back for labiaplasty as a revision. It also depends how one actually heals.
Clitoroplasty as a revision, can be seen in the same way i.e. if there are issues with first op results.
As far as depth goes... 20cm is almost 8". That is a LOT of depth to achieve in the first place, and without colovaginoplasty practically unheard of.
The average natal female depth is about 4 1/2" to 5" just to get some perspective. Most all dilators are 7" in total length as it goes!
So, why have those 8" ideas I wonder? It be a lot of 'chimney sweeping' if you'd even get it that deep. Also there is the bone of your pelvis that will put an end to depth. In my case 4 1/2" and I hit pelvic bone, which is quite normal.
Some reading for added info:
http://www.annelawrence.com/genitaldimensions.htmlAxélle