sounds like most of the issues are from improperly filled carts, or carts that are near empty getting fried.
i am on my 4th gram of oil through a single 5 ohm cart in 72 hours. some thoughts:
next virgin cart i get is gonna be 2/3 soaked in 99% iso in an attempt to remove the machine oil (not gonna immerse the heater section). after smoking a gram through the first cart, the taste did not recur on the second or third or fourth fill, i can only assume i smoked up all the machine oil and now the broken in cart is fine.
i filled the carts the same way i do my omi carts. heating the top 1/4 and the fill tool so that the entire cart is warm (without ever heating the delicate heater assembly)
i find a slight tilt (like when pouring a beer) makes certain no air pockets form.
as soon as the vapor starts getting thin, i top off. feels like that heater needs to stay WET.
i have settled on the single cart at 7.4V mainly because i hate the way the two separate barrels work. tons and tons of vapor from the single anyway, but as soon as i get a better tip figured out ill go back to doubles.
i can stick my persei tip into my skillet curve and get crazy huge water cooled rips that way!
ordered a lipo-sack just in case the worst happens while i am charging. the exploding lipo battery thing really had me worried until i realized that i have been leaving my ipods, laptops, phones etc... plugged in, and that they blow up all the time...and i just need to be careful about ALL lipo batteries, and enjoy my persei. also marked my batteries so they always charge in sequence and dont get mixed up with the extras.
made over an ounce of oil yesterday, all flavors...so time to get more carts for sure!