Trust me it is possible. How i figured it was, you can never leave a window without scrimming the top and side so as long as you can get the bulk, off your gonna have to scrim it anyway even if you just use one hand bladding. At first i was leaving a bit in the middle of the glass so id just scrim whatever i missed and as time went on i wasnt leaving any marks in the middle of the glass, just a residue around the edges which i have to scrim no matter what. The glass was spotless and no complaints. I did it even when i knew customers were watching me through the glass cos i was confident that they would be the same standard as before but alot quicker. Have you tried it? maybe you just cant do it. like i said you need good coordination.
I was crap after 10 pints!