Small & mediums for me won't cut it for a good overnight burn. They will burn hot yes, but not long, well not as long as big splits. That one round was about 9" or so. I split the wood last year for big rectangular splits specifically for overnight burns. I am still burning crap wood up first though. I am going with the rectangular and square splits to get as much spaced packed up as possible. Rounds do work good also but ya get some unusable space also. If I have any space left on top, then I add mediums & smalls to fill any gaps.