Beginners Questions on Issues - Sharp Points and Devit

I cut out 2 pieces of Bullseye glass for an eight inch plate.  In the center I put the outline of Michigan.   I followed the 2 piece, 6 mm firing (1475 F and hold for 10 min).  The results - The two round pieces for the plate fused fine.  the small state pieces 1) did not fully fuse, 2) had sharp small bumps at the points, and 3) there was some devit on the white glass of the state outline.

I have a Devner kiln, 21 x 21 kiln.  I did peek at the glass at the last 2 minutes of the 1475 hold time but did not see the above issues until the glass was cool.

I don't have enough experience to know whether to increase / decrease the temp or adjust the hold time.  Any help would be appreciated.