How about the Eleaf invoke kit one of the lovelier mods out there. I won the kit, and the tank size is a little small for DL sub0hm vaping in my opinion, but the mod itself is fantastic. You also don't HAVE to go with a kit, I find that really I'm happiest selecting my mods and tanks separately. I would consider an Eleaf invoke mod, and maybe put a Crown Uwell tank on top (either the original or the V3 seems to be the consensus). I don't sub0hm but people are pretty consistently positive about that tank, and it does offer a wide range of resistance coils so you can experiment and see which resistance you like best..
I wouldn't recommend the tarot nano for an all-day sub0hm vape. I really like my nano kit but I use it in MTL fashion, and the tank is small as well, you'd be doing a lot of refilling and recharging if you wanted to use it as an all-day, really sub0hm kit. I don't think the nano is going to suit your purposes, although I do really like it, and would recommend Vapresso, generally, as far as quality. They do pretty well, but they have kits that are larger and would be better suited to your needs, I think.
Best of luck,
Anna