(Regarding the books featuring these characters) Was PG Wodehouse writing for peers of Wooster who would relate to his escapades? Or to literate lower classes who would enjoy laughing at an upper class imbecile? Or some other group?
I doubt that he would be writing specifically for peers of Wooster, not least because he himself was not a peer of Wooster.
Wodehouse was more closely a peer of Mike Jackson from the Psmith books. Reduction in family circumstances robbed Wodehouse of a career at Oxford, sending him instead to the Hong-Kong and Shanghai Bank closely mirroring the reduced circumstances of Jackson who had to sacrifice a planned course of study at Cambridge for a job in the fictitious New Asiatic Bank.
(Mike Jackson was originally intended to be the hero of a series of books, but found himself eclipsed by Psmith whom he met at his second Public School where both were in some disgrace having been expelled from their original schools. Psmith also worked at the New Asiatic with Mike as the series progressed and in Psmith, Journalist became the unrivalled lead.)
By contrast Bertie Wooster managed not to be expelled from Eton and progressed to Magdalen College at Oxford and thence to a life of apparent leisure, though he does write a magazine column for one of his many aunts, for which he is paid a packet of cigarettes.
The Blandings novels, which introduce us to the world of the Emsworth family and their estate, if not to Jeeves and Wooster, began with Something New which was initially published as a serialisation in The Saturday Evening Post, an American magazine. While the novel was published in both the USA and the UK later that year, I think the fact of an initial American publication strongly suggests that peers of the landed gentry were not his primarily targeted audience.
Shortly after the publication of 'Something New' Wodehouse also published a short story "Extricating Young Gussie" which introduces Bertie and Jeeves, though Bertie's name is not given as Wooster and his Aunt Agatha makes clear that her side of the family at least is called 'Mannering Phipps'. Like 'Something New' this was first published in the United States in the 18 September 1915 issue of The Saturday Evening Post, and then in the United Kingdom in the January 1916 edition of The Strand Magazine.
The current incarnation of the Strand Magazine has a section on the magazine's history which states:
Founded by George Newnes in 1890 and edited by H Greenhough Smith from 1891 to 1930, the Strand aimed at a mass market family readership.
This slightly contradicts the account given in an article on the University of Victoria website:
Newnes felt there was a gap in the market for a periodical purely dedicated to the aspirational middle-classes of London
But speaking of the magazine's later development the article goes on to say:
The magazine became a mirror for the middle-classes of England, through which they saw themselves clearly represented unlike any other title available to them. This led to a large and loyal readership unprecedented by any other national magazine. The Strand would eventually grow to such popularity that it became a symbol of Englishness, representing a sense of shared community among its readers.
At the time the Saturday Evening Post was publishing Wodehouse it was under the editorship of GH Lorimer. The Post's website page on the magazine's history says that it was his aim that:
The Post would be the first magazine the entire nation had in common, and he’d achieve national acceptance by producing a wholesome, positive magazine that appealed to intelligent readers living the good American life.
While the magazines' target audiences are not identical, both were by time of publishing Wodehouse, fairly general but definitely 'respectable'. And certainly it is the case that neither are directed solely at a class of people who do not have to work for a living.
It seems likely then that, if Wodehouse considered it at all, his intended audience was anyone who might enjoy well written, irreverent farce that pokes gentle fun at the upper classes but remains inoffensive.
EDIT: I had in my mind conflated the worlds of Blandings and Jeeves and Wooster. Hopefully I've drawn a bit more distinction between them and given what evidence I can find on the target audiences of his early publishers.