i have been in your situation here is my oppinion and i am not completely sure about this but here it goes!..
you wont get clouds out of a vamo, or most vv/vw devices. its just a fact of life. No matter how good the VV/VW device is, it has an ohm limit, and you need lower ohms to vape at higher wattages. but there is more to the story than this..
lets say you have a 1.3 ohm kanger head on a vamo where you can vape at 5v. you are lookin at 19 watts. thats pretty good and should produce a large cloud right? well it doesnt because airflow and amps have a lot to do with cloud size. if there is more air flow to the coil, there will be a bigger "cloud". now, too big of an airflow hole is also a problem but that is another story. clearomisers and cartos can only supply a limited airflow due to design. also more amps will increase the amount of heat, so with the right airflow you will get a bigger cloud than the same setup at lower amps. a 1.3 ohm 5v setup will have about the same wattage as a 0.6 ohm 3.7 setup (around 19.5w).. HOWEVER, the first setup mentioned will have 3.8 amps, and the second one will have 5.2 amps. This is why people run mechanical mods that can only produce about 3.5v with a sub ohm rebuildable atomizer.
now, some people try to run micro coil RBA's on vamos and they encounter problems. the vamo doesnt work well with RBA's because of its regulation in the circuit board that causes regular errors.
if you want to get a big "cloud" you will need higher amps, more airflow to the coils, and consistent power.
i had a vamo, and all i can say is.. its a wonderfull VV device, but if your lookin for clouds, your gonna be a lot happier with an RBA that reads out at about 0.6 ohms (do not go below 0.4.. its not too safe) with a good amount of airflow hitting the coils, and a mechanical mod powered by a safe battery.
hope this rambling helped:/ !!