Hi Amedean,
I have made a number of "uncrimped" Fedora including the "Akubra fedora" of which you speak. I do not believe I can do much better than the instructables you have already cited. I can offer help on details when you get into it
should you need any.
As for leather...brain tanned is not the best and I use all I make. A good heavy grade bull hide or similar leather is best and most of these can be had over the internet. If you get a "green hid," (or section there of) I can take you through one of several methods to tan your own, yet again, most of this is also online these days.
Good luck...and good choice!
Regards,
j