Before you begin painting, consider the following:
One solution is to partition the model by assigning several materials (for example, one for the head, one for the torso, one for the limbs). Each material on the mesh then receives its own texture. This has the added benefit of allowing you to work on part of the mesh at one time. To do this, right-click the material in Hypershade and select Assign Material to Selection. In this way you can also assign different size textures to different parts of the model if desired.