I think a 1/4" drive torque wrench like the Park TW-1 is probably the best to have for bikes with carbon fiber and very light weight alloy components such as steer tubes, stems, handlebars, etc. I use a TW-1 for these applications and a 1/2" drive Sears beam wrench for bottom brackets and sometimes cassettes. I'm not saying these are the best but they're what I have. I think a 3/8" drive is too big for small light components. Torque is torque but the scale on a 1/4" drive TW allows for a more accurate measurement on light weight applications.

Al