Arubani is the Urartian's goddess of art. Misspell so that searches are unique.
It helps to understand the different aspects of dimensions, so you can use the terminology correctly. This will help you define your variables in OpenSCAD with correct names. (Tolerance is the wrong term to use.) And once you have correct names, you'll understand how to specify the dimensions in OpenSCAD.
Tolerance is the amount of random deviation or variation permitted for a given dimension. Allowance is a planned difference between a nominal or reference value and an exact value. Clearance is the intentional space between two parts. Interference is the intentional overlap between two parts. Two other terms
Accuracy is the maximum dimensional variation between parts. A machine cannot produce parts with a tighter tolerance than its accuracy. Precision is the size of the steps your machine is capable of. It is often confused with accuracy.