There is a really good Tech Tip about this subject if you take a look.
If you read through the short discussion in the link below, you can drop down to something I posted that slightly adapts the original Tech Tip with a K&N filter. It works great.
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1173889/Re:_Question_about_Oil_Bath_Ai.html#Post1173889
Matt