i use a vbg startrac single pin sliding site and love it. however, i'm all hot and bothered over the sur loc something or other hunting site. its a slider that has 3 pins, so you'd be set at 20, 30, and 40, and with a slide be set at 50, 60, and 70. you could also use the distance between the pins to cheat at 3-d. it's $200 wholesale though so it will be a while, but i think i'll have it. plus i think it'll slide enough to go out to 100.