Touring, I almost never am in dark conditions, but some trips I might go through a tunnel on occasion. That said, I almost always have one tail light turned on in flash mode, if dark overcast or foggy, I might use two taillights in flash mode.
Touring I use a Planet Bike Superflash and a Planet Bike Superflash 65.
https://www.planetbike.com/superflash-bike-tail-light/
https://www.planetbike.com/superflas...ke-tail-light/
They have many other taillights called Superflash, the above two are the ones I bring.
The Superflash has a very tightly focused beam, it needs careful aiming to get the brightest part of the beam straight back, I use that mostly on fairly straight roads. The Superflash 65 has a very wide beam, I am more likely to use that light on winding up and down roads where following traffic is more likely to be off to one side from me instead of straight back.
If I think I have bumped my light bracket and it no longer aims straight back, I readjust. I figure if my light aim is off to one side that is worse than no light, as I would have a false sense that someone saw it. I used to commute through a large university campus and I saw how a lot of college students had blinkers aiming to the sky that you did not even know they had a light until you were within 30 feet.
I use NiMH rechargeable AAA batteries for taillights, I like the white color Ikea Ladda batteries, a close second is Enellop batteries. And on tour I bring a USB powered AA/AAA battery charger to charge them up. They last a long time in blink mode, they are still bright after a week but I recharge weekly to keep them bright. If you are using disposable batteries, you might run them longer until one of your touring partners suggests it is getting dim.
Unfortunately, the lights I cited above do not have a rack bracket mount available. They do come with a seat stay mount for mounting on round tubing that is smaller than a seatpost, I wrap a strip of inner tube rubber around my rack tubing to make that thicker, and then use the seatstay mount on the rack. Put tension on the strip when you wrap it so that the rubber grips the rack tightly.
The photo is from 2012, at that time I used different taillights, but the photo is to show rack mounting which as not changed from what I currently use.
I can't remember if I ever used my dyno system lights when touring, on my last tour I only used my dynohub for charging, did not even bring dyno powered lights on that tour.
If I recall correctly you planned on being indoors once a week for an overnight. If you bring a big powerbank along to charge up things with a USB cord, you certainly could get USB rechargeable lights instead. And you could get your taillights fully charged up once a week while indoors. But touring, I like the ability to buy AAA in a store if I lose the ability to charge things up, that is why I use AAA lights instead of USB chargeable ones. I do not recall ever buying any disposable batteries on a tour, but I like having the contingency available.
If you bring lots of things to charge up from an outlet once a week, you will run out of outlets in your motel room, bring some 3 into 1 outlet expanders so you can plug more stuff into an outlet. Or USB chargers with more ports. In the photo I am using a USB charger with three ports to charge up two AA battery chargers and one Li Ion camera battery charger from one outlet. In Europe, many outlets only have one place to plug in.
