Carlos, thanks for your answer.
About the rtl video, very professional and good indeed. Those guys work marvels.
About the uncatalogued collection (enormous) I would tell you...

... to hire me until retirement age (10 years ahead) and I'll make a good excel file of it, and a catalogue, allowing you to locate any record in a shot. Excel is great, for it allows filtering by any word in the title, artist name, matrix, label & nos, etc, anything you remember from a record, allowing you to locate it fast. But for right work of that, you need :
- to put a filing number on each record,
- to keep track of where it is stored, by a key related to the physical location
- to include this information in the database
- to RESPECT fully the locations, storing the record always in the same place, aided by the numbering, or to keep track of the new location if you ever change it, even if it is temporary...
I also use a printed catalogue in the Victor fashion, stored in the first shelf of the collection, allowing to search by title, artist, genre, etc, in case you don't want to use the excel file. This collects the important info of the record, numbers and location signature.
Another advantage of the excel file is that it serves to discographical purposes, allowing to sort by matrix numbers, etc, and it's great for putting dates of recording, etc.
But I share your thoughts about the charm and fun of certain surprises and a bit of random findings when looking for records in the shelves. This is part of the fun of taking a bunch of records to carry to the music room to play... An assorted lot is better and funnier than a bunch of records of the same style all them.
The storage can be done mixing genres, etc. Sometimes a too well classified collection is boring (i e, the bunch of records taken out to play for an hour is all by the same artist or type of music.. .)
The system I use allows to have mixed records stored together if one wants, taking care of registering properly the location in the database. My collection is basically sorted by chronological order of purchase (by numbers, and the numbers are added at the moment of cataloguing latest acquisitions). This mixes diverse types of music generally in the same lot of sequential numbers, for a chase for buying records usually brings home a mixed lot. This is funny for playing a bunch of records taken off the shelf, but it is a nightmare when you want to take all records by an artist, for instance, s they are all dispersed across the collection.
Actually I keep separately 10" from 12", and some separated groups for classicsl music in 10", organ, piano and chamber, vocal, etc . The light music 10" are all mixed (thousands) , and the classical 12" too (hundreds).