Which Blériot are you trying to fly ? Do you use life wheather ? It is very difficult to handle side winds. On above picture I used the 1910 version, Gnome Omega…. I can take off and land it with damage on, but I did not log a 1 landing yet.
I’m trying the old one now (Anzani 1909) It does a very short takeoff. Feels a little like Kitfox on quarter throttle. Just let her go. Don’t force it straight, too much rudder walk during takeoff will roll the plane and crash a wing. In below video I tapped right rudder once on takeoff.
After takeoff use rudder to compensate for the curve, else it will go sharper (see your picture)
Keeping altitude stable is the big challenge. This thing is slow… It will ride on waves like a ship. I compensate using elevator when it does that… when it’s going up, direct it down. When it’s going down, direct it up. Lower the amplitude. But same time you have to use rudder to compensate the curve.
One other tip EmergencyNick provided… avoid the “aelerons”, use rudder instead. In these old planes, the aeleron was a socalled “wing warp”, you can’t see it and when you compensate too much with the rudder instead of putting it back, the airplane will go into overstress. When I’m on 500-1000 feet, I use just a little aeleron to keep course straight. See Bleriot XI - Initial thoughts