Hello!
I’d like to second the opinnion on the Fujimi kits - those babies are really fine. Watch out for the Hasegawa - not only it doesn’t have any cockpit worth mentioning, it’s also about half an inch too long when you calculate the dimensions, so I wouldn’t recommend it. The Airfix new1:72 A-4B is a beauty of a kit - you can buy a conversion (new resin nose) to turn it into A-4C - the most popular variant in Vietnam. If you want to make an A-4E or F, you need different engine intakes, so I say you either get one of the Fujimi sets, or try to kitbash something and the Airfix kit (the wings and the tail would work all right). Anyhow - good luck with your build and have a nice day
Paweł