Cotton co-sleeper/bassinet sheets?

Hi all,

We’re expecting our first child in a month, and we bought a Snuggletime Co-Sleeper for the early months.
But I’m struggling so much to find linen which fits! Snuggletime used to have fitted sheets, but they’re out of stock. From other local vendors I can only find bigger cot sheets or smaller oval Moses basket sheets.
Any suggestions or tips?

(I have also emailed Snuggletime to ask if they will be getting more stock)

Thanks so much!