How much one tightens guard screws depends on, and, varies with the material of the stock and the screw. If the stock material is easily compressed, or, the guard screw easily stretches (material too soft), then "torque" settings will vary everytime the firearm is reassembled. Stocks such as these require some means to provide stability so that good quality screws can be tightened with some semblance of repeatability every time the gun is taken down and reassembled. Enter Pillars.
Accuracy wise, guns having stocks that incorporate "pillars" can greatly benefit from some sort of uniform "torque" setting. Afterall accuracy is dependent on the ability to repeat every process from the assembly of the firearm into it's stock, the manufacture of the ammunition, to sight picture and trigger squeeze. "You have to make a perfect shot and then clone it". That's where "torque" settings become handy.
Again, how much torque is required? There should be enough, to keep the action from shifting under recoil. Guard screws should be tight. Not eyeball popping tight, but tight. If your rifle stock has pillars, or, some other aluminum type bedding block such as those like HS Precision, then the commonly accepted figure of 60-65 inch pounds seems fine. The object is not so much a specific torque setting, but something that holds the gun together tightly, that can be repeated.
So, my short answer to your question would be... it depends.