Both charts have helped me out as well. Its still best to look at everything you can online to find about everything about whatever.
In your case of this "claw" business, the leaf tips are starting to "curl downward". Curling down tips is a number of signs with different deficiencies. They will also curl upwards which in meaning can still be a "claw" as you put it.
Google diagnosis sick cannabis plants and every search that pops up will help you.
As far as nutes keep in mind that a plant with an abundance supply of light will cause your plants to grow faster. With a faster growth rate your plant will need more nutes than a plant with a lesser intensity abundance of light.
Its just paying attention to what your plant does. They will tell you quickly.