[Dixielandjazz] Chord simplification question

[Ken Gates]

I make lead sheets for our play-for-fun group of six.
We play for fun but take seriously that we want to
sound as could as we can,  which includes playing
"proper" chords.  We have two very good guitar/banjo players.
Sometimes my choice for making the lead sheet (musescore)
is a source that uses chords that are more sophisticated
than our tunes or our level of musicianship require.

So I simplify.  For example---if a see a C7-9 I recognize
that the top four notes make an Edim7.   So I substitute
that for the C7-9.

Here's the question.   Is that a satisfactory substitution or
should I consider other alternatives for that chord?  When
I play the five notes of C7-9 on a keyboard the Db sure
makes it sound like a dim chord.

I did reference a guitar book with 14 possible fingerings
for C7-9.  Three of the 14 chose the 4 notes I chose (eliminates
the root note).  Six of the 14 did play all 5 notes.  The remaining
five of 14  removed either the E , G, or Bb.   Note--our bass player
finds his good notes by ear, I don't know what he would choose
but he rarely misses.  Of course, when the banjo is used, there
are only 4 strings involved.

Ken Gates (clarinet)