Hi guys, been vaping for two weeks and loving it got a cuboid200w with a .25 , .5and ni coils. Do you have to wait till your tank is empty to change the oil ? If not how do you do so? Also how low should you let your liquid get in the tank? I'm currently running a crown u well and also have a subvape tank. Thanks guys! Have a good Night. Also looking for some flavor ideas I love fruity and pastry type flavors