It appears that the majority of Remington-Rand mechanical calculators were 10-key Add-Listers which:
The basic Add-Listers are not as desirable to collectors as the mechanical machines which perform the multiplication and division functions, often motor driven, and so there is less information about them readily available.
Remington-Rand also sold imported models of pinwheel calculators.
Several web sites have photographs and brief details of just a couple of Remington-Rand models.
For example:
https://www.rechenmaschinen-illustrated.com/ and https://www.crisvandevel.de/list.htm
The book "Antique Office Machines: 600 Years of Calculating Devices", by Thomas A. Russo, Schiffer Publishing Ltd, 2001, ISBN 0-7643-1346-0 lists 15 models of Remington-Rand 10-key Add-Listers with photographs, and one model of pinwheel calculator. This may be available to view from a library.
It is interesting to perform a Google image search on 'Remington Rand adding machine' which produces dozens of results and you may find something useful among them.
Also worth looking at is a search on Youtube for 'Remington Rand adding machine' which has various videos showing such adding machines being repaired and operating.
Regards,
Nigel Tout