My hunting bow has a fixed crawl set for 20 yards, and I don't ever intend to shoot that bow any other way, for practice or for hunting. I don't want to have to make any decisions at the time of truth other than when to draw and when to shoot. It is too easy to make a mistake and grab the string in the wrong place if you shoot the bow sometimes from the crawl position and sometimes from the normal position. Because of that, I re-tune the bow for the crawl position. I do not find that I need to use a different spine of arrow, but I do find that I have to adjust the nock point upward to get level bare shaft flight. This makes sense to me because if I’m holding the string about 3/4” lower than the normal position, moving the nock point up moves my string grip closer to the normal position. Of course, you're not going to move the nock point 3/4” up, but it could be 1/4” up + or -, based on bare shaft tuning.