Service completed this morning.  Now we are both back in our warm home.

Added new felt to the ribbon cover and some small pieces of felt to the metal stops for the space bar to knock down that space-bar racket.

In the spring when outdoor painting weather returns, I will plan to add an ivory colour to the top of the typewriter case-lid to brighten it up a bit.
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This morning I emailed Richard Polt my photo-scans of the 4-page user-guide for the Scheidegger Princess-Matic typewriter.

He should have it posted up on his Typewriter Manuals web page in a week or so.  In the section for "Princess" machines :

https://site.xavier.edu/polt/typewriters/tw-manuals.html

Currently on his web site, he has a user-guide for the Princess 300 machine...but that is only 2 pages in length.
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Found this bit of info. about the Princess Futura/Norma on a German language web site and did a translation...Princess Norma/Futura were manufactured in Germany from 1964 to 1968. 11 They were continued in the Bulgarian production as Maritsa 13 (Norma) and Maritsa 23 (Futura).

Here is the link to that web site :

https://www.typewriters.ch/collection-2/princess/

1954 Princess-Matic on the left and 1961 Olympia Splendid 99 on the right.

My top-prize goes to the Princess-Matic. 

Besides having a full Tabulator with set/clear...it is a heavy machine, feels more robust, and there is no side-to-side play of the key-tops.  It also allows me to type a bit faster with its key-slugs returning with more snap/punch.  There are also the key-tops which are a bit larger in size and it gives the feeling that have a bit more spacing amongst the key-tops.
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What paint material do you use for a key-cap?

I would worry that the paint would not hold up to daily use (especially if fingernails scratch it).