How many land crossings can Australians make into Thailand within a calendar year on a visa exemption?

Hello :) Australian here. I just wanted to ask for some information about the land crossings per calendar year. I apologise if I'm not using the correct terms! This year I have entered once by land via Myawaddy/Mae Sot for a visa exempt 30 days (after being on the first visa exempt 30 days via the airport), and once via Savannakhet/Mukdahan by land with an approved 3 month non-B visa. Is it possible to exit and enter via land this year for a 2nd land crossing visa exemption? Or does the Savannakhet crossing with a non-B visa also count? I hope I've explained clearly, and I hope someone can provide advice! Thank you so much :)