IMHO, CE4 clearos are not very tolerant of higher voltage, and really perform best around 3.7 volts and below, useable, but not the best option for the Vamo. I do have some Vivi Novas which work well on my mod, but even so, I seldom run them much above 4.0 volts. unless I am using a 2.4 or higher resistance coil.
Wattage is a different story. When you use wattage mode, the amount of power going to the clearo is automatically regulated by the Vamo. So, a 1.8 ohm coil should deliver about the same as a 2.4ohm coil, which is why many call watts mode "set it and forget it". You should be able to vape comfortably with a wattage setting of between 6.5 to 8.0 watts with most clearos. If not, then I'd consider different clearos/tanks. The iClear 30 is a great match if you like a warmer vape (top coil design), and the Kanger Pro tank is dandy if a cooler bottom-coil vape is more to your taste. I use both, based on the flavor that I am vaping.
Wattage is a different story. When you use wattage mode, the amount of power going to the clearo is automatically regulated by the Vamo. So, a 1.8 ohm coil should deliver about the same as a 2.4ohm coil, which is why many call watts mode "set it and forget it". You should be able to vape comfortably with a wattage setting of between 6.5 to 8.0 watts with most clearos. If not, then I'd consider different clearos/tanks. The iClear 30 is a great match if you like a warmer vape (top coil design), and the Kanger Pro tank is dandy if a cooler bottom-coil vape is more to your taste. I use both, based on the flavor that I am vaping.