A while ago I posted next on Tony Eyers website/Harmonica Academy..
I answered a post about having problems with hole 2 draw.
You could try the exercises as well on holes 7-8-9-10 …!!

this is the copy of the answer:
There are 2 reasons why it all feels ” different”..
1. Most brands use shorter reeds for the higher pitched harps. In general: from G to C they use long slot reeds and from d to F short slot reeds.

So , G has long slot reeds and these require a bigger embouchure/resonance room than a D harp.
And this is reason nr 2.

It takes some time to automatically have the right embouchure on a harp. On a G harp you need to lower your jaw, to have your throat more open and relaxed than on a D.

Most players are not used to play with a big embouchure and therefore most players have a problem with with 1-2-3 draw ( esp.2).

Try this ( and I wrote this some time ago in another post):
Sit down on your couch, lean backwards till you can relax your neck/rest with your head on the edge of the couch. Pick up the harp and put the harp in your mouth without any muscle tension in your lips/face…
Blow holes 1-2-3 for a relaxed chord..no more than 50% volume…simply breath out.
Than do the same when breathing in…
After that breath in again and slowly make your embouchure smaller till you hit hole 2. When you still have a problem hitting a clear draw, breath in while imagening you make a EEEE sound. From there you can go to a AAA, to a OOOH and finally a UHHHH sound. You may notice that you when you are near the OOOH the note starts to bend.

Try this exercise on all keys/harps and work your way up and down, from G harp to F harp and back.
After a few times you will start to feel which embouchure is needed for a certain key….and after while you will do this automatically

Please feel free to ask any question you have..if possible I’ll be glad to answer them.

This offer goes to anyone who’s reading this!!

………………………………………………………….

Ben Bouman
For skype lessons: search for: beta-harps or Ben Bouman

Ive got a new ish Lee Oskar in D. I had a problem with the 6 and 7 draw. where the other holes are real easy to sound and breath through these 2 are just plain stubborn. I took reed plates out to tak e alook and saw that they where all tunes and open pretty much the same – same gap openeings – no obstructions. After a couple of frustrating days of drying to flatten the reeds and then adjusting the openings – as per the instructions in “A dummies guide to..” I only managed to make things worse. So I bit the bullet and bought a new set of reed plates from LeeOskar. They came the other day, now fitted but gusee what – same problem on the same holes – ( more pronounced on 7 draw) . The reed plate looks fine. The harp breathes easily on all the other draw holes but the 7 feels like its blocked! Help

Stuart