From a "screw size" reference page:
"*NOTE: ALL SIZES ARE GIVEN IN IMPERIAL MEASUREMENTS. DO NOT USE METRIC; IT WILL RUIN YOUR SABER.*"
I believe that ktulu1347 has it though. They all should be a standard/common size, and use one or two hex wrenches.
9/64, 5/64, or 3/32 is pretty common. Some are more snug or more loose, but it's the correct tool.
Something like this would do it...
https://www.amazon.com/TEKTON-Folding-Wrench-25-Piece-25152/dp/B00I5TGXF4