Most amateur and "consumer" photographs from the pre-1920 era were contact prints. The size you cite is what you'd expect (with allowance for a slight crop by the printing frame) for size 129 roll film (produced 1912-1951), which would have fit a Houghton Ensignette #E2. Like most of the "off size" roll film formats, this one didn't ...
If by vintage look you mean grain specifically, then the following are all that matters:
Emulsion. Faster films (higher ASA/ISO/etc.) give more grain than slower films due to the way they're manufactured.
Developing solution. The chemistry you develop the film in has an effect on the resulting grain. There are acutance-enhancing developers, such as Rodinal, ...
There's a reason beginning film photography classes start with:
35mm B&W film.
Normal exposure and development.
When you know what's normal, you can sort out what factors cause what effects when you experiment with different film types, development processes and formats.
what matters most when trying to get this retro look?
Anything shot on "...
To expand on what user95069 said, it's primarily about the film being used, not the camera. I've taken multiple photos on different cameras on various film stocks, from budget point-and-shoots to automatic SLRs, and the primary factor when it comes to grain is the film and how it's exposed, and the type of camera and lens used has no visible effect on grain.
Get high ASA (that gives you larger film grain) and underexpose (that makes the grain most visible). It's actually not all that different from digital in that respect, except that the digital results are not as much grainier than they are noisier.
No, your camera is fine. You would need to do a long exposure for it to overload the receptors. You are right though. Avoid pointing directly into the sun. It will damage your camera much faster than a light bulb. If you do damage your receptors you will know it.