I owned a cleto (briefly I am a MTL vaper) and while I hated sub0hm I have nothing but good things to say about it, it's reliable, it doesn't leak, it's a pretty cloudy setup and the coils tend to last a decent period. My son owned it before me and he'd routinenly put 240 mls through a single coil (although it was clear, and citruses, so not coil killers.)
As to the pico, well, you may want something with more battery power for a "dedicated" sub0hm tank. I guess it would depend on where your wattage tops out and what battery you are using. I probably wouldn't go over 50 watts with the pico (I will say I owned one and briefly, I found I wasn't really getting battery life I enjoyed, even at lower wattages than that, but I do hear people talking about using that wattage with the pico. You may or may not need to carry a spare battery if it's an all day thing.
The only other thing I'd suggest (I am kind of hazy on what tanks, exactly will fit on there) but worst case you could get a heat sink to attach to your mod which should raise the tank up enough so that you can place a larger atomizer on the mod. You can get them from FT but if you are in a hurry, I bought a 4 pack from there and would be happy to send you one, if you'd like. Just PM me if you're interested. There is no way I will be using all 4 of them, but they can be useful things to have in a pinch, for stuff like this.
Anna