Yes you will still be able to see the crack lines unless you are able to polish the reverse side on a wet belt sander or a flat lap machine. Did you make a note of the weight of glass in your melt and the final size? That way, you will be able to drop directly onto the kiln shelf and not worry about the glass running over the edges. You could always put baffles around the edges if you are still worried. I used a thicker fibre paper in my initial melts but preferred the finish of the kilnwash shelf on the reverse. Finally, if you weigh the glass, you can get a consistent size of your melts and have a better understanding of how the patterns form if you also note how much of each colour of glass you use. Then you can experiment with different numbers of holes in the pots and see how this results in different patterns.
Crack lines
Yes you will still be able to see the crack lines unless you are able to polish the reverse side on a wet belt sander or a flat lap machine. Did you make a note of the weight of glass in your melt and the final size? That way, you will be able to drop directly onto the kiln shelf and not worry about the glass running over the edges. You could always put baffles around the edges if you are still worried. I used a thicker fibre paper in my initial melts but preferred the finish of the kilnwash shelf on the reverse. Finally, if you weigh the glass, you can get a consistent size of your melts and have a better understanding of how the patterns form if you also note how much of each colour of glass you use. Then you can experiment with different numbers of holes in the pots and see how this results in different patterns.