I absolutely loathe using a loupe - all I ever saw through a loupe was the grain of the focusing screen. It is a myth that you can check sharpness on a GG, all you can do is establish the point of best focus (the grain of any screen is too coarse, to check sharpness you need a device for viewing the aerial image with no screen). I also hate viewing cloths, and so have fit my main camera (Crown Graphic) with a Beattie Intenscreen (expensive but worth every penny) and use the pop-up hood. With this set-up, I have no difficulty focusing, even at twilight, even though I am nearly 60 and wear multifocal glasses. In the studio, where my Sinars have normal screens, I can also focus these without a cloth if the camera is shaded, but in this case I would keep a focusing cloth handy if needed. If I take the Sinars outside, I would clip a spare bellows to the back and use that as a viewing hood. For viewing processed film, as mentioned elsewhere, an old slide-projector lens makes a great loupe - it usually gives a focus about 3/4" from the end of the lens barrel, which helps avoid scratching the film.