I like someone who is willing to take a big bite!
This project will need a lot of research, so here's a few starters for your feast.
"Ospreys "Swimming Shermans" book", is a good one, more for use as deployment & colour guides.
"They are not 1/35 scale but I am sure they can be converted with a little math and a copy machine", Google Frank Krenshaw's Scalecalc for a nifty scaling tool.
Contact The Tank Museum they have(/had?) a number of drawings as per the stowage diagram, & a reference section, as well as a DD on display, so finding decent pics will be easier.
Track-Link's Resicast Review will give you an idea of what you have to do. Usefull site if you search for DD, for example.
I can't remember if Geoffrey Futter did any articles about the Sherman DD, I'll check.
The guys at MAFVA, serious treadheads, may have the odd thing to interest you, inc. back issues of Tankette.
Good luck