Aaargh, another bit of lingo to look up (RDA)! Thanks for the suggestion though, have bookmarked the wasp nano - my initial thought is it sounds like a bit of a pain having to constantly drip more juice, and not very practical for on-the-go - but OK, I can see the benefits, and like the idea of more flavour, & changing flavour more easily.
I think for now though I'm going to try a Zenith tank (which apparently has TC coils coming out soon, so can see if TC mode helps), then if problems persist will look into RTA/RDA in future.