One nice big toke should be sufficient, that's like 0.1, if the herb is ok quality. Smoking more might actually get you less high, by increasing uncomfortable physical side effects. During times when I have a low tolerance to weed, I never take more than a toke or two, that is how I feel the best from weed. So I think that what you want, might be to acquire the best quality herb available to you because the type of weed and how it was grown makes a noticeable difference.
The way to use weed these days is to smoke small amounts of high quality using an efficient method like a water pipe or vaporizer, unless you are an addict. That's right, weed use easily gets out of control for many people. The reason to smoke more than one hit, is if you are using it all day and have developed a dependence. Then, I cannot even feel the effects of one hit, and have to smoke multiple massive ones to get where I want to be. And if I don't do that, I am going to feel like utter crap. So the best thing to do is avoid this shit by keeping both your frequency of use and dosages low, while seeking out the best herb for maximum enjoyment. I say this because cannabis has turned out to be the most addictive substance I have tried, by far, and the effects of overuse have been pretty devastating on my life at times.
I would recommend against ever redosing with cannabis, the risk of addiction is just too high. Once you get stoned, do not choose to experience it again until you have been sober for quite some time... it will just be a diminished return.