[wazzz]

Here's what I do. I use a small 1/4" torque wrench to drive a 10mm socket. I cut a length of 10mm Allen wrench to make a stub of roughly 1 inch long. I use this stub as an adapter between the spark plug special tool and the 10mm socket.
May be you could do this with your 3/8" torque wrench and a 3/8" 10mm socket.