.25 is an odd thickness to print because it is 1.5 .2mm layers. On thin things like that I like to keep it in even increments of .1mm or .2mm. So I either print 2 layers of .1mm to get .2mm or increase the thickness to .4 and print 2 - .2mm layers. You could do 2 layers of .125mm That way you get 2 layers laid down in different directions and this will be stronger than just 1 .25mm layer.