Rand, and some of the Asha'man are the only people we know the maximum Gateway sizes for. Same with Elayne in LoC and CoT (a jump in size), Aviendha in tPoD and CoT (again a jump in size) and perhaps Cadsuane in WH.

Cadsuane is an interesting case. At a time when Elayne and Aviendha are making Gateways a little taller than a man, Cadsuane has no issues making a Gateway large enough for a tall horse and its rider to go through with ease. Elayne and Avi catch up, of course, but we don't even know if Cadsuane was making her maximum size, and she still seems awfully close if strength is the sole determiner.

Then we have Egwene in tGS offering to open a Gateway for Bryne's army to pass through. I doubt she's offer to do it alone if all she could manage was something eight feet by eight feet. She can obviously make one bigger, and that's a reflection of her great strength and likely a considerable amount of Talent.

For that matter, even Logain's quote is telling. He's able to see a difference between his Gateways and Rand's at quite a distance. Which means there's a significant difference in size, which doesn't explain the fact that they're very close together in strength. Rand obviously also has a good amount of Talent, which can also explain why Asmodean found his skimming platform impressive.