This can be uncomfortable over the two-hour duration of a movie. Keep in mind that any given projector only has a fixed amount of light. So if you spread that light over a larger area, the picture will look less bright than it will if you focus all of that light on a smaller area. A common mistake that is made is going for the biggest possible screen, and overstretching the ability of the projector to produce an ideal picture. Yet even this is a matter of taste.
Some people prefer a bigger image that is a little less bright and lower in contrast.
Others will prefer to limit the image size in order to maximize brightness and contrast. Actually, you can get many fabrics cut to whatever size and custom aspect ratio you want. This aspect ratio issue warrants some attention. But the width of the image is usually the same in both formats. So you might as well set it up to get the biggest image in this format.