Well, Okieboy…
You have really got your work cut out for you. Right off the top of my head, I can tell you that besides the cupola, the tracks will have to be replaced, the drive sprockets will have to be changed, the rear deck will have to be retooled in parts, the fan outlet on the turret will have to be moved/changed, the location of the headlights will have to be moved, and several other modifications will have to be made depending on what time period the Tiger was produced. This is a project for a person with a lot of time, and patients!!
You are going to have to invest in some books. I own "Achtung Panzer No.6", and highly recommend this book. I have heard that "Germany's Tiger Tanks D.W. to Tiger I" by Thomas Jentz & Hilary Doyle is the essential Tiger I book, but have not been able to get my hands on it. I think it is out of print. I can also recommend Tank Power No. 13, 14, and 15. They are produced by AJ Press. There are a lot of CAD drawings of specific tanks in these books (not all of them correct). Also check out this site: http://tiger1.info/
The zim will be a very easy job considering what else you will have to do. I imagine a saw blade would make a perfect applicator, and you can use most modeling putties for the actual zim.
You also may want to check out VP’s 1/15th scale Tiger ( http://www.verlinden-productions.com/product_listing.htm ). It is a later version, and VP also makes a zim kit to go with it.
hope this helps, and good luck with the endeavor
edog