If I were you, I wouldn't mess with anything too much this close to hunting season. If your arrows are tuned, and your broad heads are flying true, I'd practice realistic hunting shots, from here on out, at the 3D course. Don't worry about the "x" ring, but rather, worry about the proper placement for a kill shot at whatever angle you're shooting from.
That being said, I also know the value of shooting a lighter weight set up for longevity of your bow shooting career, and the inherent emphasis that it places on your shooting form. Inconsistencies become much more apparent, and it's much more difficult to get off the string cleanly, with a light weight set up. You'll really start to notice the need for back tension, consistent grip, bow arm and shoulder placement and follow through, anchor points, and notice the effects of grip and/or string torque!
I hunt with bows in the 47-52# range, and my off-season practice bow is 38#! If you don't want to mess with your trajectory and sight picture, just make sure your lighter "3D" set up is shooting close to the same speed and grains of arrow per pound of draw weight.