Doing some quick, rough​ number crunching, looks like you could do a monster scale model using BT-52 tubes for the outboards and a BT-80 for the core. Length would be about 38.7" for the Proton/Salyut launcher.Peter Alway's "Rocket of the World" has dimensions. It looks like the core is about 4.1 m in diameter. Each of the booster pods are 1.6 m in diameter. The maximum diameter across the booster pods is 7.4 m.
It's still listed on the NARTS web store for $30: https://blastzone.org/nar/narts/store.asp?groupid=1080035015601Tone Deaf: Alway's book is even more expensive at Amazon. Nearly $200. It is a much sought after book, and has been out of print for a number of years.
"Tone Deaf",Thank you so much for those dimensions. I've been trying to pick up Alway's Book on ebay used. I will not pay the 100+ bucks some people are asking. I missed out on one three weeks ago that went for about 25 bucks plus shipping.