Been monitoring George Mayhew and Steve Jennings on this subject. I just wanted to add that the 5 draw is often bent in blues, as a kind of lower auxiliary note.
Little Walter does it in "Juke." Listen to the Draw 5 that starts the third verse after a lead-in. He starts the note bent, releases it, then bends it again on the way down through Draw 4 in a descending lick. The bent Draw 5 on the way down sounds almost identical in pitch to Blow 5, but it's definitely a bend.
In the fourth verse, just after coming back to the E-chord from A, he does a little "tickler" lick twice, where he plays Draw 5, bends and releases it, then plays Draw 4 and 5 blow. The effect is completely different than if he had used blow 5 instead of a bent Draw 5.
Or listen to Sonny Boy Williamson's "Bye Bye Bird," after the vocal verse where he swtiches to a regular C harp from the low 365 he plays up to that point. Leading into the D chord, he wails out a bent 5 draw, in utterly characteristic fashion.
If you listen to your blues records, you can probably pick put dozens of other examples. The Juke ones I remember because they've been burned in my brain for over 20 years - they're a complete and unparalleled education in what makes that bend so sexy!
Who cares if it detunes your harp a little? You can always tune it up again. I'd set my harps on fire if there was a good enough musical result from it.