Love mine! We have used orange, yellow, and are on reds and they are great quality.
Are you using them from birth?
I think you could turn the reds and trifold the short way (they would be about the length of a yellow that way), but they would be very bulky on a small baby and would have a lump in the middle from the thick part.
You could get the organic yellows, which are a bit bigger than regular yellows, but I still think you'd want to size up at some point.
I think Flip organics are the best one-size insert but are more expensive. The econobums are a bit longer and skinnier so are short and bulky for little babies.
To really get a good fit at all sizes with one diaper, I'd consider padfolding GMD small flats. You could double as baby gets bigger if needed.
Also consider selling one size to fund the next!