Vintage,
Any oil is better than no oil. To battle flash rust (although my methods may seem ****), I do the following:
* The slide:
I now use a light coat of gear oil. I had been using Lubriplate for years, but it holds grinder dust, saw dust & metal shavings. Gear oil seems to do better. Just wipe down the slide & re-oil as needed.
BTW; For aesthetics, I apply silicon grease to restored vises that I sell.
* Bare metal components:
For the handle, anvil, & jaw faces, I apply a light coat of WD40. Seems to work for that, and I have a couple of gallons of it.
Otherwise; I clear coat these areas on restored vises that I sell, and advise the customer to apply light oil as the clear coat wears off.
* A couple of other tips:
1. Keep your vise covered with first, a large piece of cotton (an old shirt will do), then a garbage bag over the fabric. That will keep dust & moisture out, and eliminate condensation.
2. Periodically clean & re-lube your vise.
Happy Trails.
Edit: I believe ATF will damage paint.