Great info. I'm thinking I may have to give this a go.I used caustic soda to sort out the stuck post after watching a video on youtube. You need to cut the post down leaving about an inch protruding from the frame. Fill the seat mast with a mix of CS and water. The solution slowly eats away at the alloy post and after 5 or so fills it will be the thickness of a coke can. Pull whatever is left of it out with pliers. The CS does not affect steel. Make sure you use gloves and a mask.
I broke the top off the post in the vice, using the frame for leverage, after spraying for two days. Cut it down to just below the damaged area, and hammered the micro adjust back into the post. Fortunately it's now at the correct height for my short legs