Beonin:

Knife of Dreams
Chapter Two
The Dark One’s Touch

As soon as Tervail let the canvas fall, she embraced saidar and wove Spirit almost caressingly. This weave fascinated her. a rediscovery of something thought lost forever and surely the greatest of Egwene al’-Veres discoveries. Every time she wove it she felt a sense of wonder, so familiar as novice and even Accepted, that had not come to her since she attained the shawl. Something new and marvelous. The vertical silvery line appeared in front of her, right atop the scoring on the ground. and suddenly became a gap that widened, the view through appearing to rotate until she was faced by a square hole in the air, more than two paces by two, that showed snow-draped oaks with heavy spreading limbs.

for argument sake we can call this 7 feet by 7 feet (1 span = 3 feet) since it's a little more than 2 paces x 2 paces

Here is the largest one we've seen from Egwene:

A Crown of Swords
Chapter 12
A Morning Of Victory

Weaving a gateway where he had been practicing the sword, a good eight feet by eight, she stepped through onto what seemed to be a ferry, floating in darkness that stretched forever.

So Egwene creates a gateway approximately 30% larger than Beonin can ... that's nice until you realize that Beonin is no stronger than Melaine who is approximately half of Egwene's strength. Either Egwene should be able to create a gateway that is 10 feet x 10 feet (which makes her like 70% Rand's strength) ... clearly we would have seen that by now if she could pull it off. Alternatively Beonin at her strength level should only be able to create a gate way about 5.75 feet x 5.75 feet if she was of "average" Talent.

I would also state it is highly unlikely that Egwene has a weak Traveling Talent since she discovered the weave for women and that seems highly unlikely if she did not possess a good strong talent for it.

Rand Quote
Chapter 54
To Caemlyn

The gateway appeared at the foot of the steps, first a bright line that seemed to turn, opening into a square hole into blackness four paces wide. Not a murmur came from the Aiel. Those beyond would be able to see him as through a smoked glass, a dusky shimmering in the air, but they could as well try walking through one of the palace walls. From the side, the gateway would be invisible except to the few close enough to see what might seem a long, fine hair drawn tight.

Four paces was as large as Rand could make it. There were limits for one man by himself, Asmodean claimed; it seemed there were always limits. The amount of saidin you drew did not matter. The One Power had little to do with gateways, really; only the making. Beyond, was something else. A dream of a dream, Asmodean called it.

I acknowledge that you can make at least a couple of arguments here ... Neither woman looks to have strained to create their gateways so we can even be sure these are as large as either woman can manage. But this is what we have to go on. I'm inclined to think Egwene could produce a somewhat larger gateway than she did in this scene. It was, after all, for only her and Lan ... and you could just as easily argue that Beonin showed no strain and only had 2 people to Travel with as well.

But based on Aviendha's gateway in TPoD I suspect Egwene can create one of at least 9x9 since she is stronger than Aviendha in current strength..

The Path of Daggers
Chapter 1
To Keep The Bargain

Aviendha focused, and the flows wove together, creating identity between this place and the place she and Elayne and Nynaeve had chosen on a map. She gestured as though opening tentflaps. That was no part of the weave Elayne had taught her, but it was almost all she could recall of what she herself had done, long before Egwene made her first gateway. The flows coalesced into a silvery, vertical slash that rotated and became an opening in the air, taller than a man and just as wide. Beyond lay a large clearing surrounded by trees twenty or thirty feet high, miles north of the City, on the far side of the river. Knee-high brown grass came right up to the gateway, swaying through in a small breeze; it had not truly turned, only seemed to. Some of those blades were sliced cleanly, though, some lengthwise. The edges of an opening gateway made a razor seem dull.

The gateway filled her with dissatisfaction. Elayne could make this weave with only a part of her strength, yet for some reason it required all but a fraction of Aviendha’s. She was sure she could have woven a larger, as large as Elayne could, using the weaves she had made without thought while trying to escape Rand al’Thor what seemed a very long time ago, but no matter how often she tried, only scraps came back to her. She felt no envy – rather, she took pride in her near-sister’s accomplishments – but her own failure made shame surge in her heart. Sorilea or Amys would be hard on her, if they knew that. About the shame. Too much pride, they would call it. Amys should understand; she had been a Maiden. There wasshame in failing at what you should be able to do. If she had not had to hold the weave, she would have run away so no one could see her.

Given Aviendha's perspective on how tall a man should be that makes this gate way at least 7x7 and she says Elayne can create a larger and thinks she should be able to as well if she could remember her original Weave. That means Elayne potentially has a Stronger Talent for Traveling than Egwene (because she is currently weaker) or that Egwene can create a larger than 8x8 gateway. Or both!