hello,
I have the gws Pt-17. It has only 2 ailerons, so does not roll fast. It is very scale like with the stock motor. I found it to be very stable and a good aerobatic trainer. With my model motors mini ac, 3 cell 2100 thunder power, 3.8:1 planetary gearbox, and a 10 x 4.7 apc, the stearman becomes a rocket with 2 wings! At close to 2 to 1 power to weight, it is not surprising you can climb out of any trouble.
The down side of biplanes is the extra drag the second wing creates. I have found it is not as good in the wind. You should never fly in wind with stock motor. If you do have a brushless setup, you can try to fly in the wind. It just does not like to penatrate. Biplanes are slow compared to monoplanes. When compared to a flying wing monoplanes and biplanes suck in the wind....get a flying wing for windy days
"when the airplanes come in (due to wind), the flying wings come out"
theHarpmanDan