The limousines lined up early at the Hotel Pierre to drop off the women who are Bill Blass' friends and customers. Inside, in the Cotillion Room, Nancy Kissinger, Susan Brinkley, Estee Lauder, Pat Mosbacher, Casey Ribicoff and at least a dozen other "names" sat with store presidents, buyers and press as Blass showed his new spring collection.

Before buyers and press found the folding wooden chairs marked with their names in the showroom area of designer Harriet Winter's loft, Winter greeted most of her guests with a kiss, thanking them individually for coming.

At the crowded Nipon show in the auditorium of the Parsons School of Design there were empty chairs assigned to U.N. ambassador Jeane Kirkpatrick and television personality Phyllis George. Those seats were quickly filled by others once the show began.

This is the last lap of the spring fashion marathon that began a month ago in Milan, continued to London and Paris, and will finish on Seventh Avenue at the end of the week. But although the names and the settings may be different, the prize is the same -- consumer dollars. Also similar is the way the designers here expect to win favor with customers, offering slimmer, shorter, more colorful clothes.

Backed by a tape of Leon Redbone singing "I want to be seduced . . . I want a woman to take me out to dinner," Blass showed a leaner collection than he has lately. In contrast to his fall collection -- more often long than short -- most of his designs for spring are cut off at the knee. He has used a generous dose of shirring to tighten the fit of clothes, a treatment popular in France this season, and big bows are plopped at the shoulder, the waist, the hip, even the hemline.

Several in the audience preferred the less fussy styles. "I loved the things with straight skirts," said Kissinger after the show. "I can't afford to buy something this year that will be out of style next year," said Brinkley, describing a favorite tame and tailored style. The women also applauded the bright colors, as in a suit that mixed tomato red and tangerine and pink, shown with a bright green scarf.

Blass' new jacket is a short, flyaway style, which he showed as a suit in lightweight cover cloth or in checked wool with a red leather skirt. There are no pants. "What's new about pants? Everyone's got 'em, babe," he said before the show.

What everyone doesn't have is his exceptional bead embroideries, made in India from the Irving Penn photos of flowers and shown off on a short flyaway jacket worn over a full skirted gown. Most of his evening dresses are very narrow, often gathered and shirred. "My full skirts are for Washington ladies," Blass said.

At the Harriet Winter show the models appeared, one at a time, one of the first wearing a raincoat in what Winter called "my favorite fabric, 100 percent plastic." Another modeled a rainsuit of black plastic and beige canvas, described as "painter's drop cloth."

Winter's strong suit are these coats, sometimes in bright yellow or embossed with patterns, but always in plastic or reasonably rainproofed canvas. Her jackets are best when collarless and uncontrived, of a fabric that looks like a handwoven rug, in a mix of colors that makes it easy to wear with any color or with black.

Pearl Nipon hasn't forgotten the faithful customers of her easy-fitting dresses. While the Nipon signature tucks are used less frequently in this collection, there is still a characteristic young, pretty look in pale wallpaper prints and white organza.

The Nipons have borrowed the plaids popular with kids in Europe for easy-fitting trousers and tops.

As usual, Pearl and Albert Nipon walked the length of the runway after the show. "I'm taking each day as I usually do," said Albert Nipon when asked about his recent indictment for tax evasion and bribery. "I'm addressing myself totally to this business."