Air Dam for 1/8 Scale

[circus162]

I've read up on air dams on hydros to prevent blow-over, and the consensus seems to be to use 1/4 inch, but all the boats mentioned seem to be under 36". My question is that on a 1/8 scale hydro should I still start at 1/4 " or maybe start at 3/8" because of the size of the boat?
Thanks,
Rich

[JimClark]

modern boat or an older shovelnose?

[circus162]

Modern boat--'88 Miller High Life

[circus162]

Any Ideas?