Building new studio - (how to build the man window?)

Hello, I am building my new studio in my new house. I will post pics in a sec (need to shoot them first :-) My main concern is how to build the windows between the control room and the live room. I have built 2 in the past, but they were not very effective (sound proofing wise). Is there drawings/plans/tutorials I can see? The windows to the outside (garden) will all be alumminum frames with double laminated glass (one with 8mm and one with 6mm). Doors in the studio will be build the same way. I have 2 concrete walls separated by more or less 10cm, separating the control and live room. This is where the "problem windows" is to be placed. Another question: Sould I leave the space between the 2 walls empty or should I fill the gap with some absorbing material? Look forward to hearing from you asap. Kind regards Joni ps- I leave in Mozambique, so there are no professionals to help or specific studio materials so one needs to improvise.

http://johnlsayers.com/Recmanual/index.htm If you go to the above link, on the right hand side, under the construction section there are various examples of construction methods and explanations to go with them. Within this document (created by Mr sayers himself) you will find details of window designs. Hope this helps :)