I use the same Kohler filter, usually about $10.50. There is a 'NAPA Gold' sold at NAPA for about the same price. I don't have the number here but they can reference for you. I'd like to find a less expensive one myself.
I've been using Puro L10241s on my 15hp Courage (Gravely ZT) for the past couple of years. Based on the lengths motorcity listed, I can see where the longer filters could be a problem. The 10241 fits with room for rags underneath (keep spillage off the transmissions) along with space to work a socket wrench cap for removal.