First, welcome to the Forum!
What you need is a good book about H.M.S. Victory. There are three on the market that contain spar dimensions.
I think my first recommendation would be the old classic, The Anatomy of Nelson's Ships, by C. Nepean Longridge. The title notwithstanding, it's a book about how the author built a 1/48-scale model of her that's now in the Science Museum of London. It contains a set of beatiful, detailed drawings by George Campbell, and lots of advice on modeling techniques.
Another excellent source is Anatomy of the Ship: the 100-gun Ship Victory, by John McKay. This one contains a fabulous set of drawings (numbering in the hundreds); Mr. McKay is an absolute master of the old-fashioned art of drafting. If possible, get the second, revised edition. (The first one contained some mistakes, which, to the credit of both author and publisher, got corrected in the revision.)
Mr. McKay also contributed the drawings in Alan P. McGowan's H.M.S. Victory: Construction, Career, and Restoration. This one reproduces many of the drawings in the Anatomy of the Ship volume, and some additional ones. The coverage of the rigging is actuallyl more thorough in this book.
Unfortunately all three are pretty expensive. But I think you'll find any of them an excellent investment - and they'll provide many hours of interesting reading and inspiration.
Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.