Arrow stiffness (spine) needs to be matched to the draw weight and draw length of the bow, and to a lesser extent point weight. The higher the draw weight, the stiffer the arrow needs to be (same is true for draw length). A given arrow spine rating may work OK with a range of draw weights, say like 50 to 55 lbs, 55 to 60 lbs, etc.

If the bow is set at 50, the arrow spine needs to be acceptable for the draw weight at that draw length, with the point wieght being used.

If a beginning shooter can handle 50 lb draw, and has a bow that is adjustable to 60 lb, it would be a good idea to buy arrows with a spine that is acceptable for 50 to 55 or even 50 to 60 lb draw weight if possible, so he can crank the bow up a bit after a few weeks practice.

Assuming all is fine at 50 lb, the effect seen by cranking the bow up will be a somewhat flatter trajectory (slide sight pins down to compensate), and likely some slight change in left to right impact. These are to be expected and can be corrected by adjusting sights.