I just got some 'woody weights" the other day and did a little testing with them on some tapered Chundoo shafts. These shafts are spined 70lbs and are being shot out of a center cut 57# non ff recurve.
Shaft 1 without "woody weight":
27.5" to b.o.p.
weight with 3 5" shields and 160gr point= 532gr
f.o.c.= 14.55
GPP= 9.33
Shaft 2 with 125gr woody weight
27.5" to b.o.p.
weight w/3 5" shields and 160 gr point= 660gr
f.o.c.= 19.09
GPP= 11.58
Both arrows shot well out of the bow but the one with the "woody weight" is quieter and penetrates deeper into my target. It does impact a little lower at ranges of 30 yards but out to 20 it is right there with the other arrow.
Certainly nothing scientific or unexpected here but it did increase the foc and quiet the bow, and at least in this case didn't seem to effect how they shot