It may or may not help to test on a setup similar to one you plan to vape on. Testing on and rta won't necessarily give the same flavor if you normally vape on an rda and vice versa.
Next to an rda's simplicity I use an ehpro bachelor like an rta the way it was designed. When the tank is empty I can unscrew it from the deck and it's got to be one of the simplest for wicking. A postless deck with ample room for a single coil, slide the cotton through it and snip at either side of the deck. No tucking, no fluffing. Screw the tank back on and vape what's soaked in the cotton. Doesn't require large amounts either, maybe an inch long piece. The nano version works the same way, just with a shorter chimney.
If trying flavors I get a more accurate idea even though it's a bottom coil rta and the vapor has to travel up the chimney because that's how I'd be vaping it normally. An rda would likely be simpler since the cap just pulls off rather than threading on, flavor may be different though. I'm sure there are other rta's out there that can be removed, where the juice flow shuts off (no tipping the works upside down like a kayfun that leaves the juice ports gaped open) and exposes the build deck.
An extreme example would be something like an rda vs a mtl rta like a kayfun v3/4/5. The same exact juice would taste quite a bit different from one to the other and it's possible for a juice to taste great in one setup and mediocre in another depending what flavor profiles come through.