I think you're going to have trouble shooting a 48” bow with a 29” (let alone a 30”) draw. Probably the bow is stacking at that draw length, and it certainly has finger pinch. Both of those problems would make it difficult to shoot the bow with any degree of accuracy. Using a fixed crawl means you are gripping the bow string lower than the bow was designed to be shot. I would imagine, though I’m not sure, that this would have a greater effect on a short bow than it would on a longer bow. Given how the deck is stacked against you, it doesn't surprise me that you are having trouble hitting at 20 yards.