Hello, Jazmaan and Gnarly.
Gnarly: Again, this is my ignorance of terms speaking. My apologies. I know nothing about overblows, except that I can't play one, that is, until a few days ago, on my circular diatonic harp. I've been trying to do that for years, on my Richter diatonics.
To me, an "overblow" or "overdraw" is a sharped (raised) pitch of a harmonica reed, done on a diatonic or slide chromatic harmonica by a changing of tongue position and mouth shape, not using the slide button.
To me, a bent note is a flatted (lowered) pitch of a harmonica reed, done on a diatonic or slide chromatic harmonica by a changing of tongue position and mouthshape, not using the slide button.
Jazmaan: Your observation that chords wanted on a circular harp may be in a position not easily playable is correct, as far as I know. I've tried a few simple pop tunes with the circular diatonic and slide chromatic, and the results at this time seem to agree with your observation.
But, the circular harps have so many chords available everywhere on the harp, that finding a substitute chord should be as easy as moving over one hole in either direction.
As a chord-melody harp, I haven't seen any better arranged note placement. But, it doesn't have "all chords," only the chords that fit for a diatonic scale, through 13ths on each note of the scale. In that way, it's similar to a Chordominica II, but with many more chords.
My Seydel Chromatic Deluxe Baritone Circular is a prototype, and won't be lent out. Someday, I may get good at playing it.
John Broecker