You have to hold the glass horizontally when you apply the collodion. How to hold the glass is different from person to person. I personally hold like “flemming’s left hand rule”. (I’m not sure the actual “flemming’s left hand rule is like this..)
I hook the thumb on the corner and hold the glass edges with the first finger and the middle finger. I used to get my fingers cramped and drop the glass often, but now I can hold 8×10 glass easily.
I try not to have the collodion come all the way to the thumb, my plate is always missing the image in one corner.
Since 8×10 is the maximum weight I can hold with “flemming’s left hand rule”, I need to support entire glass underneath using all of my fingers. Some people do this way for smaller plates like 4×5 or 8×10 but I didn’t do this because I heard that the temperature of the area that each finger faces under the glass raises and it prevents the collodion from making a smooth image. (And I may drop the glass if I hold like this.)
I will try to this new way to hold the glass for my first 11×14 in near future. I get pretty nervous because if the glass becomes bigger, the effort for recovery gets bigger..