Ok, I've made another video with my fit changes. I measured my inseam again and it came out about 89.5cm, so I lowered my saddle down to 79cm. I found a seat post with a bit more setback and moved the saddle back. I've also raised the handlebars by maybe 3-4cm, and added 1cm to the stem. I think this gives me around a 5cm difference between the saddle and the handlebars.

I can see in the video that my back is straighter, but isn't quite as straight as it could be, yet. How does this look to you guys?
Thanks a lot!