When I first started messing around with carbon I tried weed whacker string, it was just too noisy, and it would make my nocks pop off all the time. Instead I started loading up the point, this seems to work the best, I shoot a Titan with GT3555's 50 grain brass insert cut to 29.25" with a 145 grain point. They weigh in at 475 grains. I have been messing around with an internal footing, by gluing 1/4 inch wood dowel cut to 1.5 in the point end as well. This has added around 15 grains. Stuffing them works but for the heck of it mess around with FOC.