I can't speak for other nations around the world but the alloy 6060-T6 (a better version then 6060-T5) is quickly become THE standard alloy for any profiles. Bascially this means that when you go down to a local hardware shop overhere that the standard alu profiles are of this alloy. The older standards of 6063-T4 and T5 are being replaced and we are the better for it. 6060-T6 has a 0.2% yield stress of 160 MPa and get therefor stand up to 60% higher stresses before sustaining a permanent bend. This is good if your rudder stock takes some abuse from time to time but it also measn you have to excert more force to permanently bend it yourself. Just as a comparison steel typically has yield stress limits in teh range of 300-750 MPa. So it should not be too difficult to bend these alu profiles.

Often the standard sections are not anodised but unless your stock are permanently submerged in salt water they don't need to be either. Especially not for your first try. You'll get several years of surface out of these just the same.

Wouter