A piece of glass doesn't really have a definite front or back side, it is up to the glass artist to decide which side they prefer. If another glass artist tells you that glass does have a front or back side, well.... they are sadly mistaken. It is all up to an artist's personal interpretation! When using Dichroic glass in fusing, it is true that you cannot fuse a Dichroic side to another Dichrioc side but that is not exactly what we are talking about in this mini lesson.
Now having said that, there is a "right and wrong" side to cut your glass on. I'm talking about cutting with a hand held glass cutter. If you are going to use a band or ring saw, then it doesn't matter which side you cut on! As for using a hand held cutter, you should always look for the smoothest, shiniest side to cut on. You have to push the glass cutter's wheel along the surface of the piece of glass to score it. For that reason you need the flattest side to cut on. It's extremely difficult to push a cutting wheel along a pitted or rippled piece of glass. Heavily textured glass typically has one side that is not as textured as the other.
So if you decided, when you were in the planning stage of your window (picking out the glass), that you really wanted a piece of stained glass that had it's heavily textured side to be facing the front on your window, that is still easily do-able. First you need to cut out your paper pattern pieces, follow our tutorial on cutting out patterns HERE if needed. Then when you get to the paper pattern piece that you want to adhere to the piece of glass that has a lot of texture on it's front side, flip the paper pattern piece over and glue the front side of the paper pattern to the back side (which will be the smoother side) of that textured piece of glass. Be sure to still get the grain of the piece of glass correct or it will look wrong later!
Once glued on to the back side of the glass, you should be able to hold that piece of glass up in the light, look through it (if it's transparent) and see the pattern piece looking the way it should look when the piece is finally cut out and laid in place ready to be soldered.