i'll wager to say that allot of the flutter problems come from the hole size drilled in the control horn for the pushrod clevis. most drill bits drill larger than their size and add to that a little wobble from a hand held drill and you can end up with a fairly loose hole where there should be little to no play. for drilling those control horn holes, get several sizes of undersized number or letter drill bits and by drilling try holes in a piece of scrap approximately the same thickness and material as the control horn,, find the exact size that fits the clevis pin or pushrod snug......it will make a difference.