I found that I can fit a standard Teflon muffin tin in the Sun Oven if it is rotated 90 degrees so that it is perpendicular to the gimbal.  This works when the oven is tilted way up to its maximum position, however, the front three muffins are up against the glass as they rise.  If the oven is in the lowest position for midday summer sun, the muffin tin does not fit.  When the oven foot is in the 4th hole down, the muffin tin is mostly flat so this is probably close enough for summer cooking given the normally hot outdoor temperatures anyway.  This picture was taken on Dec. 31 in Colorado when the outdoor temperature was 15 degrees Fahrenheit and the wind was blowing at least 25 mph.  The oven temperature was between 200 F and 250 F degrees and I brought my oven in when a wind gust blew the reflectors out of their thumbscrew holder.  The muffins had cooked for about two hours and were not completely cooked.  They had risen at first but later fell.  I finished cooking them in my oven in the kitchen.  The flavor of these cranberry orange muffins was fine but they were short and dense.