I stitched this mask on felt both with, and without a stabilizer.  Both were OK, but I think the best choice is to hoop a firm cutaway stabilizer and then lay over it the stabilizer without hooping it.  The design stitches in three colors.  When it is finished, remove it from the hoop and trim away the edges and eye openings, leaving as much felt as is desired and leaving stabilizer  to the edges of the mask.   Then, place the mask face down on paper, and cover the back with glue.  Lay over it a contrasting sheet of felt and trim again, grading the edges, if desired.  You may glue the two layers before you trim and save a step, but the mask is nicer when the two layers are both clearly visible.  Sew,  or tie on, an elastic cord.  The design works surprisingly well in other colors combinations.  One of my grand children has one stitched in red white and blue, and several of the others chose      green combinations.

 Mask in one  file

118 mm X 179 mm, 16,400 stitches

dst...exp...hus...jef...pes...thr...xxx

 Two halves of mask in two files

 100 mm by 100 mm, 9,361 stitches

dst...exp...hus...jef...pcs...pes...thr...xxx