What's amazing is that when you consider Alaimo came from a theatrical background yet managed to dial it back JUST enough for TV, it's even more impressive
Actually, I don't think he did dial it down. In my admittedly non-expert opinion, Alaimo, Robinson, and the other actors working in big prosthetic masks didn't dial it down as they acted -- they kept up a very theatrical style, because that's the only way to get emotion through the makeup. The makeup makes it feel subdued enough for TV. If the makeup weren't there, they'd probably come across as being a bit too theatrical.