vertex group question

Im trying to skin my character, and have come across 2 different methods to connect points to the bones- the one is by using weight painting, and the other is to select a group of vertices, and assign them to a vertex group, (if im not understanding something here please point it out)

now if for example you picture the hand, I want all the vertices of the hand to be 100% influenced by the hand bone, and the arm to be 100% influenced by the arm bone, but where the two meet, I want there to be a slight transition, so lets say the wrist will be 50% influenced by the hand bone, and 50% by the arm bone

now as far as I can see the weight painting method has that nice coloured representation of red=100%, yellow 50 and blue=0

but when using the paint method, I dont feel like I have full control, so is there a way that I can select vertices and assign weights that way(without using the paintbrush), yet still have the same visual representation of red=100% etc

In the Vertex Groups panel you can manually enter a weight and click “Assign.” The selected vertices will acquire that weight for the current group. You will see the colours in weight paint mode.