Found: Vintage Nikon Flash Heaven
I spent a little time Googling "Nikon SB-24" and some other models, looking for a site that might have a little chart comparing them, and came across a wonderful Nikon fan site run by a guy in Malaysia. It has a full page dedicated to each of the flashes in the Nikon family tree.
It has detailed descriptions of all of the older Nikon flashes that you can use when you are cruising eBay for some bargain off-camera lumens and photons.
Below are several direct links to many of the most appropriate Nikon flashes. These all have PC connections and manual control, so far as I know.
If you are into the old Nikon scene, explore around his site a little. It's a hoot.
SB-24 | SB-25 | SB-26 | SB-27
SB-28 | SB-800 | SB-28dx | SB-80dx
More recent stuff here:
Nikon Flash Comparison Chart
And, just for fun:
A Pictorial History of Nikon Cameras
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