The TFM editing tool allow you to adjust font dimensions easily.
You can adjust glyph dimensions by pulling the character box with the mouse:
You can also modify the ligature/kern table. The kern's, for example, can be adjusted by shifting the second character with the mouse. Or - if you prefer - by just entering the value. TFM editor also has an auto-kern feature. Use it to create a kern table instantly for a font that lacks one.