I'm considering adapting a seatpost, i.e. extending it with some aluminium tubing. I know nothing about types of aluminium - would either 6082T6 or 6063T6 be appropriate?

I dug up some blurb:

"Aluminium alloy 6082 is a medium strength alloy with excellent corrosion resistance. It has the highest strength of the 6000 series alloys. Alloy 6082 is known as a structural alloy. In plate form, Aluminium alloy 6082 is the alloy most commonly used for machining. As a relatively new alloy, the higher strength of Aluminium alloy 6082 has seen it replace 6061 in many applications. The addition of a large amount of manganese controls the grain structure which in turn results in a stronger alloy."

But found no mention of weight.