I wanted to start trying to customize harmonicas and trying different tunings etc. the one that most interested me was tuning a harp to play “on the road again” by Canned Heat in my opinion one of the best and first of the white boy American blues bands along with the Great Paul Butterfield. The reason for this I won’t lie, there were lots of vids on you tube. So I got and old harp in A and very delicately filed the 6 draw hole. There was a lot of trial and error so much so my Wife said it sounded like I was torturing some tiny woodland animal ( she’s very dark and quite possibly disturbed 
) finally I got it, to be honest getting used to the new bend in the reed was a bit difficult but any after more trial and error. I thought it was getting there, so I started to play along it was ok, but not great continued to keep having a go until finally boom! I got it now I’m nailing it every single time. Now this old harp is sounding great, next I’m going to sand the plates flat on a wet and dry stone, emboss the reed holes and re-gap it all. I’m very happy and pleased that my first venture into customizing has been a success.
Be prepared to re-tune some of the reeds after embossing and re-setting the gaps. It might not be necessary, but usually several reeds will need “touching up” – especially after embossing.
– Slim 
Yes Slim, I’ve already thought of that I’m doing everything very slowly and deliberately taking my time with each step. But it’s going very well. I’m very used to precision work as I used to scratch build very detailed models. Many of the skills and tools have come in very handy
Did the embossing today, but not to my satisfaction, my 5th draw reed keeps sticking. I had most of the morning with it as the Wife had gone out with her bestie, so that gave plenty of time to mess with it, and swear at it quite a lot. I’ve flattened the reed plates and sanded it so now it has a more response, and it’s more airtight fixed all the reeds except the one I’ve mentioned they are louder and respond better. It does great overblows now, there’s a lot less effort in doing those. Just that one pesky reed I’ve got to do. I think some rubbish may have got in there I’ll deal with it tomorrow as my wife has not long returned
Well, not only 5 draw but also 3 draw, but I was correct in assuming there was some rubbish trapped in there. Some slight burning was restricting the reeds, went over them regapped them all good now