Good luck. Most remaining Slingerland snare wire sets are on the drums. Some other manufacturers made repro's up to around 2005. They are certainly hard to find in really good shape. I have a '58 RK and the wires are a bit stretched with 2 missing.
The metal tabs aren't the best method of applying tension. It's either on or off. Fine tuning is better left to string or fabric - not metal. I'm surprised Slingerland used this style for 3 decades. Easier to find these with 1 or 2 tabs missing....and you can cut your
own tabs and rivet them on.
The actual length is a tad less than 16".....about 15-7/8".
Could you recommend a material for cutting your own tabs and any specific rivets? Sounds like you may have done before. I do have an extra S2016 which is for the clamshell strainer which I believe is the same wire set, just with the rivet holes open for the screw instead for the clamshell.
You can order a foot or yard of the material in the proper width and thickness. Cutting the strip lengths could be done with a simple pair of tin snips or bandit cutter. Home Depot might have that kind of material and cut it for you to length. In fact, the Damage Control took kits we had in the Navy had the metal in about the correct width and thickness. It was strong and flexible enough to wrap around 4" to 10" water pipes. I think a fairly thin grade of aluminum would work. A similar tool for flaring cymbal rivets would work as well. Lots of ways to do it. You could consult a machine shop. I personally have not actual done this but have been considering it for a '48-50 Slingerland RK snare drum I have. I have a used 16" wire set and the 2-1/4" metal tab on the butt side. But need to install the 3" tab for the snare side end.