MEANWHILE, AT A FAKE BARBERSHOP …As the “Beastomorphs” shoot continued, a short called “Uneek Kutz Barbershop” taped on the other stage. It had a cast of seven and had required the speedy construction of an ersatz barbershop.The sketch was about a Black barbershop that offered a “radically new alternative to mental health treatment for white guys.” The “Uneek Kutz” sketch, which starred Domingo, Brennan, Mikey Day, Ben Marshall, Kam Patterson, Kenan Thompson and Jane Wickline, required plenty of wigs, like many “S.N.L.” sketches. The show has an in-house wig shop at 30 Rock and keeps more than 3,000 wigs there.New wigs take at least 80 hours to make, so Mancuso relies on existing ones for the pretapes and modifies them as needed. “Saran Wrap, tape,” she said. “We’ve been doing it the same way for a very long time.” Thompson, the “S.N.L.” stalwart, appeared in “Uneek Kutz” between rehearsals back at 30 Rock.“Shout out to the wig department for always finding a new do,” he said as a hairstylist peeled the wig off his forehead. “Because this guy definitely exists: Gray dreads pulled back into an up-pony — it can’t always be Afros.” The built sets are a marvel of ingenuity, teamwork and efficiency. Andrea Purcigliotti, a production designer, said she and her colleagues don’t know which sketches might air until Wednesday afternoon and don’t “really, truly start drafting” until about 10 p.m. that night. Construction begins late Thursday afternoon. The barbershop set for “Uneek Kutz” was considerably more elaborate than that of “Beastomorphs.”Decorators got clippers and scissors from a barber supply store in Irvington, N.J. They rented vintage wall art from local prop houses. The graphics team created portraits of Barack Obama, Shaquille O’Neal, Jesse Jackson and others. Barber chairs and other larger items were rented from a Long Island prop house. Costuming takes a similar scramble. On Wednesday nights, Jill Bream, who oversees it for both pretape units, begins what she called a “costume design triage,” determining what’s in stock, what can be modified, what to buy. For the barber jackets, her team called barbershops and beauty suppliers until they found the right ones. Then the in-house graphics team designed a Uneek Kutz logo and the jackets were sent to an outside vendor for embroidery.The jackets were ready by Thursday afternoon. Michael Che, right, who wrote “Uneek Kutz” with assistance from Carl Tart, left, observed the shoot from behind the cameras. The production was more fluid and faster paced than that of a typical TV set. The segment director, Chris Werner, kept the cameras rolling as he called out directions and the performers adjusted, tweaking and improvising on the fly. Che offered notes. “When you write a sketch, the production onus sort of rests on you,” Che explained later. “If the hair is wrong, if the wardrobe is wrong, if the set’s wrong, if the shot’s wrong, everything — it’s really kind of up to you.” Patterson, who played a barber, said the freewheeling approach helped him find the “magic.” “I’ve been in a barbershop my entire life,” he said. “So I was just going on what Che and Carl put on paper but, you know, playing around with it a little bit.” After the director yelled cut, a woman brought a platter of cupcakes. It was Patterson’s 27th birthday, and everyone sang “Happy Birthday” as he blew out the candles. “Now the Black version!” he shouted, and people joined him in Stevie Wonder’s “Happy Birthday.” At exactly 1:59 p.m., the assistant director called out, “That’s lunch!” — a full minute ahead of schedule. Domingo was whisked out the door by his handlers.