I think it would be more helpful to buy a 1/4 inch drive beam wrench. It should give more accurate measurements in the lower torque range needed for critical parts like stems and brake levers. A 3/8 inch drive could cover the rest.
I use a 1/4 and a 1/2 inch beam wrenches. I bought the 1/4 inch for the bikes and the 1/2 inch for cars and trucks. The larger one is good for bottom brackets.

Al