Hi. I recently repaired my manual window regulator in my car(the one that lift the window)(attached photo)while i apply to the gears new grease. The window regulator operate manually(no motor)and has metal drive gear and plastic driven gear(attached photos). Since there was a plastic driven gear i used a synthetic grease(silicone based oil(150 Cst)+lithium complex thickener(NLGI-2). My question is not about the type of the grease that i should apply to the gears(mineral,PAO,silicon etc) My question is how should i match the viscosity of the base oil of the grease and the thickener to the application? In my case,since the gears operate manual,what should be the viscosity of the base oil and the thickener and if the plastic driven gear was,also,made of metal,was it matter?(i refer to the viscosity and the thickener,not the type of the oil/thickener) Thanks in advance.