As an advocate of toilet seat etiquette, I am deeply offended by some of these posts. Sorry Ted, I overslept.
https://www.msu.edu/~choijay/etiquette.pdf
These are great L1 rockets, they're practically made for it (minus a couple Ns.) A successful L1 flight is by no means impossible built stock, but I personally would change the shock cord to 1/4 kevlar.
That would be my guess, every market of everything has some people like this looking to exploit the unknowing. After all, there is one born every minute.
Split fins tend to whistle either way. I don't think it will spin, as the fin is still in line with the air frame. Unless it bothers you, there's really no need to fix it.
That's the crux of the biscuit right there. I'll order from Dave again, probably soon. I always give him a call beforehand to check stock, and he's always happy to do so. I've always found him pleasant.