I cut a notch out of the center of the filter and just put in one.
Also, I use these (cheaper)
Fresh wave odor packs $9 for 6 compared to $16 for 2

https://www.amazon.com/gp/product/B00F2PS8HK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1