Hi, i'm currently printing http://www.thingiverse.com/thing:403244 with a 15cm diameter. The first half took ~ 5 days and turned out very well. I'm still struggling with the second half. I'm using a 0.25mm nozzle and i noticed that leveling the bed gets really tricky when dealing with such small margins. I can even tell whether my glass plate has uneven parts. The first layer is printed thinner in some areas.