I have some Whites Smokejumpers that I have had for 15 years. I treat them, and use them out in the woods without any trouble at all. I use Sno Seal, but I think just about any bee's wax treatment will work. I bake it in to the boot using the cracked-door oven method. I really lay it in thick to the stitching.
On all leather boots, I could care less if they have a GTX lining. eVent I don't mind as much, because it doesn't hinder breathability.
On all leather boots, I could care less if they have a GTX lining. eVent I don't mind as much, because it doesn't hinder breathability.