I suggest that you use BirdFont and follow these steps to import your work in the editor.
Draw a triangle and a rectangle. Use them as test shapes to decide what your x-height should be.
Compare your test glyphs to other fonts using the preview tab. (Ctrl+p)
Turn on grid and guidelines for x-height and margin. Create four rectangular markers at the bottom line, baseline, x-height and top.
Save your glyph template as SVG. (Edit -> Export glyphs as SVG)
Open your glyph template in Illustrator and turn on rulers (Ctrl+r). Drag down new lines from the ruler to the bottom line, baseline, x-height and top positions.
Insert your glyphs in to the template file.
Resize the glyph.
Save your glyph with a different name.
Import the file in BirdFont. (Edit->Import SVG)
With newer versions of BirdFont and Illustrator can you also copy and paste glyphs between the two programs. You still need to decide what your x-height should be but you might save a few seconds if you skip the step where you save the glyph as a separate SVG file.