Etymology of "If I had my druthers..."

The online Merriam-Webster says the first known use is from 1870, and The Phrase Finder quotes the January 1870 edition of Overland Monthly and Out West Magazine as having this:

If I was a youngster, I 'drather set up in any perfession but a circus-driver, but a man can't always have his 'drathers.

I believe that is likely the form that the first usages took, and shows the humorous intent of the phrase, with the "punch" of the humor coming at the end of the line. (It also shows its use in American dialect writing, and perhaps that it hadn't stabilized on the druthers spelling/pronunciation.)

Further research shows an earlier instance, one which shows the same structure. It is from an "Original Dialog" section of the 22 August 1868 issue of Oliver Optic's magazine: Our boys and girls. The piece, Before Vacation by Peregrine Breese, has this passage:

Isabella. I am sure I don't care what any of you like; but Saratoga or Newport I still cling to; there, now.

Susan. There was a queer old lady in our neighborhood, who used to say, "Well, some druther have this, and some druther have that; but all of us can't have our druthers." We shall see!

This seems unlikely to be the earliest use, but perhaps nearly so, and is likely to have something like the style of the original use.

I believe that "If I had my druthers" = "If I had my 'I'd rather'" = "If I had my say" = "If I were to say my opinion".

I think it fits perfectly. Anyone agrees with me?