As mentioned above. I would go tubus front and rear racks. Ive seen a few racks and these seem to be the most simple yet well made racks around in my opinion.
In my opinion theres only 2 brands of panniers i would trust on a long tour.
1. Ortlieb. These are the ones i use and have about 3k miles on them and never had 1 single problem. Theyre water proof, and have a great mounting system that allows you to mount and remove with just the pull of the handle.
2. Arkel. In my opinion just as good as Ortlieb but not waterproof.(waterproof covers sold seperately). These are also top notch panniers and offer alot of pockets so u could manage your things a little bit better.
With either of these two panniers, you will never have a problem.
Good luck!!!