'Very expert' seems excessive to me… I was even getting a bit tangled up myself.
The harmonization you did seems good, except for the G over Db7 on beat 2 of the second line; I would have harmonized it without the Ab, which clashes a bit with the augmented eleventh and, above all, sacrifices the third; then the Bb7aug should be a dominant chord, so with the Ab.
I tried to harmonize the other notes, but I must say I am not very satisfied (besides, this harmonization method also has its limits).
I used Ebdim a lot, both on C7 (as C7b9) and on F-7 (as VII to harmonize non-chord tones), and also on Bb7, treating the Bb9 as an F-6;
in the third measure of the first line I added some tension to the C7, to make the melody stand out a bit more;
in the last measure of the first line I used a diatonic harmonization of Eb to avoid repeated notes, but it doesn't blow me away;
in the first measure of the second line I used a double chromatic approach; alternatives could be an independent lead in which the three lower voices harmonize A natural with B natural, D, E natural, but it's not very nice; at most you could try harmonizing it with C13b9; all to avoid repeated notes (which, in the end, aren't actually that terrible).
I harmonized the G over Db7 in drop 2 to free up the lead a bit; in tight voicings it came out as a somewhat harsh chord with a sound slightly different from the rest of the harmonization, all in the upper register; in the following measure I harmonized the Eb over C7 with C7#9b13 - I don't like the #9 with the perfect fifth and, yes, there is a repeated note :) There are probably others, I'll look at it more closely later and see if anything else comes to mind. Take a look and let me know if the math adds up for you.