Have always dug Roosters. Have 4 now and recently thrifted a vintage bow tie that was originally labeled for the Bowdoin Pharmacy in Kennebunk, Maine. It's size and condition make me think late 60's early 70's.
I get that. Unfortunately he looks about 12 so to these old eyes it looks like Paul Muni's great-grandson found a trunk in the attic. I think maybe an approach like Lapo's; take the classic elements of grandpa's wardrobe and add a personal twist would be better suited to him than just a slavish imitation of a period's fashion, especially if the period is a very stylized one like the 1930's. Again, my opinion.
The suit is gorgeous and well-fit but you've got to get over the whole hat thing, it makes it look costume-y. And with your diminutive stature it makes you look like an extra from "Bugsy Malone".
My father worked on the Santa Fe RR as did his father before him. However when he wore a wristwatch it was an Omega Constellation. The pocket watch would be my choice although you should anchor it to the button shank and not the hole itself or put a heavy fob on that end and thread the chain through the button hole into the watches opposing pocket.
My father told me that a gentlemen must always have on his person a pocket knife, a pistol and a clean handkerchief; everything else would follow.
My must haves are PS, cuff links, tie clip, money clip/cc and biz card holder and a wedding band which is the one thing I'm NEVER without.