Can you post images on here?
Instructions on how to post images here:http://www.frit-happens.co.uk/forum/index.php?topic=23036.0
If your kiln is firing say 15 or 20 degrees hot, that's still 20-25 degrees below a full fuse on float glass - so you'd still get a tack fuse on the float, whilst over firing the bullseye...
As a guide, I have to fire one of my kilns at 795 to get a good full fuse on Bullseye, so that's a good ten degrees lower than recommended. All kilns are different.
And as Flame and Fuse suggests, if it was only single thickness glass (glass likes to be 6mm thick) you're likely to get needling at the edges, shelf paper or kiln wash, as it tries to 'pull in'.
As for getting the shelf smooth, getting rid of brush strokes, when the wash is completely dry, simply rub over it with something like kitchen roll, on the flat palm of your hand, usually a circular motion, but nice and gently. You can get a really smooth finish.