A four-blade easel gives you much more freedom to place the image where you want. As you've discovered, the 24x36 image doesn't fit well on most paper unless you do as mentioned above, crop or use an off-center image or make test strips first though I find this to be a pain.

There is sometimes unwanted empty space or objects on one side of the frame that lets me print to a full or near-full 8x10 but the rest of the time I just plan on matting it as I want. However this presumes you are cutting your own mats, otherwise you'll need to shoot and print "to order" as mentioned above.