Unlock the Secrets to Resize a Vintage Knitting Pattern

Can I knit this Sirdar pattern in my size? Go from a pattern written only for a size 34 inch to 51 inch size using knitting math. Some hints and tips to help you get started knitting a vintage knitting pattern. I walk you through my "secret" process to adjusting a vintage pattern to my size. Is it the same as yours?

Sirdar polo shirt pattern from the 1930s/ 1940s adapted to use cotton from Hayfield Raw Cotton Classics DK in my stash.
Other FOs
Blacker yarns - https://www.blackeryarns.co.uk/
Scottish yarn festival - https://thescottishyarnfestival.com/
Bow Fiddle yarns - https://bowfiddleyarns.com/
The Cocoon Tree bag
https://www.etsy.com/uk/market/cocoon...

Chapters:
0:00 - 00:27 Intro
00:28 -1:41 2 main reasons people don't use vintage patterns
1:42 - 2:44 Larger patterns alternatives
2:43 - 5:12 Chosen pattern challenges
5:13 - 5:52 Measurements
5:53 - 9:32 Yarn assessment
9:33 - 10:09 Tension swatch
10:10 - 12:29 Substitution of yarn
12:30 - 14:15 Pattern modification
14:16 - 21:51 Cast on and knit
21:52 - 22:16 First try on
22:17 - 22:43 Final reveal
22:44 - 24:39 Bonus FO 1
24:40 - 27:11 Bonsu FO 2