I have done this shop b4, a couple of them. It is easy in a way and cumbersome in the other way. If the loud music and the "perfume" don't nauseate you, U will be alright.
U R making sure the sizes are there in the store. Best thing to do is in the DUDEs section ask for Small size, and in the BETTy's size asked for XL. The object is for the associate to check the sizes or use the walkie-talkies. But keep in mind that neither sizes are in the store. This store focuses on the Hollywood scene. If they are not chunky in H'wood, that store won't have chunky clothes.
The mannequin clothing, just request to purchase it. The associate should suggest other articles of clothing or the companies web site to purchase the item.
You might be stressing to much. If U R going to cancel did it b4 the last day of the shop so I can pick it up. I am not a size one but I find those shops pretty interesting.
As for name, pick a associate any assoicate, approach them and say, "excuse me the young man/woman up front...." The associate will say who "Bob, Billy Tasha aksaha." U say yeah. "They help me very much, they need a raise." and the other name is usually on the receipt.
Then push the handicapp door button (to see if the door works) and leave the store.