The IGC information is here
https://doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=439739&page=1

Nigel Brown's "British Gunmakers" Volume 2 "Birmingham, Scotland & the Regions" has a list of DOM by SNs

As Stan said, Lewis promoted heavy fowlers

[Linked Image from photos.smugmug.com]

but also made a lightweight hammerless 12g "The Aeriel"

[Linked Image from photos.smugmug.com]