About this tweezer;
Dimensions: 130x35x12 (mm)
Minimum 10 Newtons (1kg) of preload at the holder tip when fully closed.
7MPa of stress occurs in construction when the tweezers are fully closed. %100 infill ABS's yield strength is approximately 30MPa.
You can scale the part smaller and change the infill rather than calculations. The part's yield strength should be ok for your use.
There is no detail smaller than 1mm feel free to use coarse settings.
Recommendation: calculations are made for the %100 infills with standard ABS. If you don't have any concerns about calculations you can print the file however you want.