Storage categories

Like the many peoples on Earth, there are just as many ways to mount your stamps. I say to mount them YOUR way, the way that pleases you the most.

I am not sure I understand all the aspects of your question, but here are some general comments. I do not know what you do today and assume "sleeve" means what most call "mounts".

Most printed albums I know always group stamps by issuing entity so if a country changes name in the process it will get a new page grouping.  Countries are mostly sorted alphabetically.

For example, stamps issued under British control as British Guiana will be on pages labeled British Guiana and those issued under Guyana will be in a separate group in a different album. Malaya/Malayasia is another example as some states (like Johore) issues stamps under at least 3 or 4
entities since the region kept changing. In some cases Australian states (like Tasmania, etc) appear following Australia.

This means albums are sorted by issuing entity. Now, you can resort pages by continent or even region such as British Africa, British Asia, etc.

The organization by country often depends on what catalog used or implied by album maker. For example, if it follows Scott numbering, the semi-postals, airmails, etc. will be in a separate section after the regular issues. Some albums will be more chronological without regard to definitive, commemorative, airmail, etc.

Unless you have a very specialized album, you are left to own methods to organize the stamps that do not have a space in the album. You may just want supplement the album pages with your own. Some actually create custom pages and others may use Vario pages or other similar products to keep these with the associated material.

For my US collection, I actually redid pages to add minor varieties not included (maybe color, watermark, year date, tagging, etc(. This often meant replacing a page with more than one pages.

For my worldwide collection, I use Steiner pages and they also follow Scott but Steiner tends to put minor varieties on a separate page following the regular varieties. When I get to the point of adding custom pages, I will follow that. I have resorted some countries like Malaya/Malaysia.

Your choices are influenced by the printed album you use as a base. If you go it alone, it is up to you.

I do not know what you meant by protective sleeves. Do you mean the 8.5x11 plastic sleeves? If the are good ones archival types that is ok. A practical item is a Vario sheet. It is a durable page made of safe plastic with varying pockets for items. I keep spares and as a staging area prior to mounting,

A quick way to get some ideas on various aspect is to look at some youtube videos.  There are quite a few on collecting but some are much better than others.
I wish some organized groups took more advantage of this over a traditional approach.