I have three torque wrenches. One for inch pounds, one for medium torque values and one for high torque values. Yes, they are expensive, but well worth it if you are going to work on engines.
You can use adapters to use 1/4" and 3/8" as well as 1/2" sockets on any torque wrench. However, if your torque wrench will only work for the values stated on the wrench. If you have to torque something over the highest value on the wrench, that you will need the next size torque wrench to do that.
Torque wrenches are more accurate in the middle of their full ranges. If the wrench is good for 30-100 foot pounds, it will be most accurate for values between 45 and 85. For values below 45, move to the smaller wrench and for values above 85 move to the larger wrench.
Last thing. Don't use your torque wrench to take nuts and bolts out. Use your other wrenches for that. Use the torque wrenches for torquing nuts and bolts only and set the wrench to its lowest value before putting it away at the end of the job.