numlockedI disagree with balcony being the less favourable route. you're less vulnerable, more options for places to go if you get jumped, and you can still reach everywhere you can from train except for balcony but why you'd want to focus so much spam on the enemy demoman I don't know.
I find it as a more passive option, when you go balcony you are in a position where you cannot follow up that well and your team will rely on good team work with the soldiers and the scouts, it can be effective in a organised team but if your team is disorganised you can just find yourself with the enemy pushing over your team quickly.
I also focused on the normal route more because this method can transfer to other maps like gullywash and viaduct but I forgot to mention that part.
DuckyReally loved your writing style and although I don't main demo it was still very informative!
What I would recommend you doing is turning this into a YouTube series to reach a wider audience, maybe flying around the map with noclip with Byte's drawing tool to help demonstrate your point.
Read my earlier reply, I'd love to but it would take longer to produce as I've never done it before, and I feel a lot more comfortable explaining something in writing.