if you are willing to REALLY do it period......
These are the drafting systems I have collected so far. I own the physical copy of Cornwells and McDowell, and I redid the entire Devere's scans page by page to straighten and cleanup the online copy I found.
6.3mb - Cornwells Victorian Cutting Method - 1888
http://www.victoriansweatshop.com/Ga...hod - 1888.pdf
9.6mb - Garment Drafting Systems/Devere 1866 v2
http://www.victoriansweatshop.com/Ga...re 1866 v2.pdf
518kb - Devere Rulers
http://www.victoriansweatshop.com/Ga...ere Rulers.pdf
(note regarding the rulers PDF: if you print it with NO scaling, landscape, on 11x17 paper they will be accurate.
24.6mb - Devere's Ladies Costume Patterns
http://www.victoriansweatshop.com/Ga...e Patterns.pdf
2.2mb - McDowell - Using the machine
http://www.victoriansweatshop.com/Ga...he machine.jpg
62.4kb - McDowell Drafting Ad
http://www.victoriansweatshop.com/Ga...rafting Ad.jpg
2.9mb - McDowell instruction book 1885
http://www.victoriansweatshop.com/Ga... book 1885.pdf
EDIT: to fix links