How to scale models properly through script using Attributes?

So anyways

I need to scale models using attributes

which will be a vector3 value

these are the same 2 models with different vector3 values in size for the attribute

how would i properly scale them without using anything else like an iv loop to make them the same size of each part

For example if a model is 10 ,10,10

and another model i want to scale to is 50,50,50

I want the model to become from 10,10,10 to 50,50,50

while still maintaining the scale of all the parts in the model

I tried dividing 50/5 and using the value of 5 to multiply the size of 50,50,50 to every single part

now the problem is that since i do this to every part it ends up becoming bigger

does anyone know how I can get this to work?