re the cooling diagram, I can only say that it looks too complicated. I'm also not a Weber expert.
I would hook it up exactly like a 69 Mustang with webers. Excepting the "Y" pipe at the front of the engine that the Goose uses from T-stat outlet down to pipe to up front (hot water out). Also, the one small connection at the bottom of the radiator is different.
All the rest of the connections could be made as if it were a simple Ford. That is what I boiled my drawings down to...while comparing to a very original car with water valves...and then there was my car with nothing left of the valves, and no crossover between the two heater core hoses, BEFORE the shut off valves that I installed in the cabin for emergency and ease of activating heater! Yes, it gets used in my car!
ZF comes out while tipping engine forward...loosen everything that would allow you to do this...take off dist cap....
While engine is tilted forward, you can take off front jackshaft pulley. This makes pulling engine easier.
Then take off starter, bellhousing, flywheel, and block plate. This really makes pulling engine much easier!