My seat post removal advice is as follows
Forget about penetrating oil etc. Strip the bike of its parts. Is the seapost expendable? If so, take the saddle and wheels off the bike and saw the current post 1 or 2 cm from the top so you've removed the saddle clamp section and have a nice bit of...
Subbed - looking forward to seeing the finished product! I'm so tempted to raid the savings and buy this!
https://www.ebay.co.uk/itm/Trek-8000-19 ... Swba1dFSV7
This is lovely and I'd be surprised if someone didn't snap it up - that seems like a very decent price. If you do decide to split and would be prepared to post, I'd be interested in the saddle and potentially tyres