I'll agree with Deep Sea Gull here,
If your connections are strong (i.e. tested) there is no reason you can't go past 50% drag relative to breaking strength. That said, the type of fishing you're doing, your rod, and your physical ability all play into it. For example, if you're jigging for AJ's then setting strike at near 40% (can you and your gear even handle 32#'s drag?) is not bad since the goal is to stop the fish right off. However, if you're fishing for something (tuna) that runs some distance you might be better off setting the drag lower at strike.
2 of the biggest issues people forget when fighting fish is that the drag increases in direct proportion to the diameter of the spool + line remaining AND that the drag increases dramatically when more line is in the water due to drag. Understanding these effects (as well as knowing the strength of your connections) is key to administering the max drag at a certain point during the fight. Sadly there is no easy answer. Obviously you can use 25% at strike and 33% at full as is prescribed, but to move beyond that requires an understanding of what is happening to your reel and line at that given moment. Truely as much art as science.