“vary to” is correct and usable in written English.
You can use it as a phrasal verb meaning “to differ or change to something else”. Example: The terrain in this area varies to hills and valleys.
Hire a mariachi band (prices vary) to sail with you.
Residents pay annual dues, which vary, to the homeowners corporation to maintain the island.
Residents pay annual dues, which vary, to the homeowners association to maintain the island, Mr. Tartaglione said.
Inevitably costs will vary to the extent that the length and format of monographs vary, which is to say substantially.
But what sort of change that moment will bring about....well, that can vary, to say the least.
The basic cultural pattern is very similar to that of the K'iche'or the Kaqchikel; custom and dress vary to some extent from one municipio to the next.
Power can vary to either axle depending on wheel slip.
How they do so will vary to some degree, however.
He's also adding disclaimers, including "individual results may vary," to packaging.
However, the quality and quantity standards for the rock dust vary to some degree.
We observed that for different tissues, the preferred features vary to some extent.
