One thing that strikes me from looking at your latest sample is the inconsistency in the width of the numerals. /5 is way too wide. /7 is too wide too. /2 and 3/, on the other hand, are too narrow. But that's just the numerals relatively to each other. Given that your letters are pretty wide (or at least some of them, such as the dominant /a), perhaps you should use the width of /7 as your reference point and adjust all other numerals to match /7.
But the degree to which different letter slant looks inconsistent. /c/ looks more upright, /f/ looks more slanted, etc.
Note that the "vertical" stems aren't supposed to be parallel to each other. Check out any professional typeface, and you'll see they make compensations in this department. For example, /f/ would almost always slant less than other letters, because the curved ends already contribute to the impression of a slanted axis.