This piece of bad design fails to cover consistently, will not get between lace eyelets and lugs, will not get under the lug where the leather can fail for lack of treatment and will not get the liquid into areas where one layer of leather is stitched to another unless ...
... Unless you just squeeze the heck out of the bottle and make it drip all over the place so you can get into the tight spaces. Even then, you have to wrestle with a dripping boot.
I had to go back over each boot three times in order to get the whole boot treated. In the top picture, look at all the light-colored spots. Those are from the uneven coverage that required one more treatment.
Nikwax obviously has no one with serious boots to test this on.
Anyone with a recommendation for a serious, professional solution please leave a comment.