Help finding right tuning .....

I think I got it .....
Low end of a F rather than high end of F_low
Went back to this :

youtu.be/YGU3Cdk_lgY

And compared harps.....
Now got this :

soundcloud.com/michael-miller-547891485/nucity

" Blow draw into 3, then 4, then 5, then 6, then 7…! The switch happens between holes 6 and 7. From holes 1 through 6 the blow notes are lower than the draw notes. From holes 7 through 10, it reverses. The blow notes are higher than the draw notes."

Is there a type harp that maintains the low blow notes from end to end ?

Seydel makes circular tuned harps. I have a friend who converts standard harps to circular for a fee. He has to move reeds. PM me if you want to contact him.

One thing about circular, you probably have to dedicate yourself to it. No switching back and forth between Richter and circular. The alt tunings I use are all based on Richter and I can move between them easily. My friend Dale only plays circular tuned harps.

Have you looked at chromatic(?). Playing tunes in any key is possible on a chromatic; valveless chromatics are fairly cheap, if you want to try one.

"Just switch reeds" is actually a lot of work. If you wanted to try Circular I would recommend just buying one. 
In D? Circular harps are labeled strange. I think they label them by the note in blow 1, but they play in the key of the note in draw 2. Take the diagram linked above for example. What may have started as a Bb harp that would play in F in second position, now is a C harp that plays in F in second position. Don't take my word for it, I have not kept up with circular tuning. Not my thing. I THINK an A circular would play in D major, but I could be wrong.  
If you want to try one, Rockin Ron sells them:

rockinronsmusic.com/collections/seydel-harmonicas/products/melody-king-tuned

I second Keith's idea. One chromatic replaces 12 diatonics. Never a missing note. But there is a bit of a learning curve. It took me a couple years to learn to play in 10 keys on a chromatic. You can learn the major scale on a diatonic in 10 minutes. I love playing the chromatic, but still use diatonics for many tunes. 

> That's a strange way of describing the system.

First time it has made any sense to me ..