For loaded touring (especially with front panniers) I'd go with bar-end shifters. They might look stupid, but you'll have much more control over steering, with all the benefits of reliability and friction option of downtube shifters.
Don't forget the amazing ability to shift with your kneecap while climbing out of the saddle.
Don't forget the amazing ability to shift with your kneecap while climbing out of the saddle.
Fuck that hurt.