thats the best way to do it.
I tried looking up sizes but there is just no real record and the only way is to measure what you have to know what size you need.
Im personally trying to find universal vacuum hose with colored stripes on them. Everything I keep finding is geared towards GM with some geared towards Ford but Ford from the late 60s early 70s more so than 80s.
I have planned similar to what you are doing, I am going to run all new vacuum lines and keep the originals and box them up and put into storage. I want to get rid of all the emission systems as well as the vacuum lines for it and all those plastic vacuum tubes and replace it all with just plain vacuum hose.
"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2