I don't know nuthin, but I would be really suprised if the long seatpost had anything to do with the frame defect. It seems in the wrong place, and as long as you had enough post in the hole, I don't see the issue.
Re: sizing, if it works for you, then it works. You might have long arms and legs, in which case you will end up with a small frame and riser stem and bunch-o-spacers, and a size larger will stretch you out too much. If you are a heavvy dude, you will soon notice if all your weight is on your hands.
I don't know nuthin, but I would be really suprised if the long seatpost had anything to do with the frame defect. It seems in the wrong place, and as long as you had enough post in the hole, I don't see the issue.
Re: sizing, if it works for you, then it works. You might have long arms and legs, in which case you will end up with a small frame and riser stem and bunch-o-spacers, and a size larger will stretch you out too much. If you are a heavvy dude, you will soon notice if all your weight is on your hands.