Why don’t you have the option of including Super and Subscripts in the normal font? As long as you’re not using an old version of Word, OpenType features are supported.
FontCreator 6.0 does not have the option of adding OpenType super/subscript features, but there are other methods (this one is for Windows XP only). Later versions of FontCreator made it a lot easier.
If you have the Standard or Professional version of FontCreator, you can use Glyph Transformations to scale the glyphs and make them bolder in one operation.
This is the result that the default script produces:
Some manual adjustments are likely to be necessary afterwards if the font has serifs.
