Sturtz, I tape all the gaps on my planes. Don't know if it stops flutter, nobody will say for sure, but I still do it. Central Hobbies offers a product call "Trim Seal" that I used at first. It's an iron on thin, very thin, product that works very nice. When I ran out of that I just went to same color monkote. Just cut a small, narrow strip and iron it on. I think I can tell a slight difference in the authority of the controls. But it just could be in my mind. Nothing else in there might as well be that.
Thanks,

Barry