vg is thicker to wick and wicks slowly.
topcoils with long wicks take longer to wick because the liquid has to travel upwards.
both those together is a recipe for dry hits.
add some water- about 10% by volume to thin the liquid.
for topcoil
tanks, give the tank a twirl once in a while to wet the top area where the coil is.
once the water works and you know how much water to add, in future you can use distilled water; or bottled water; if you boil some water in a pot, use a pot cover, and try to capture the condenseed potcover water - that is distilled water. You will easily capture a few milliliters of distilled water from a potcover.
You ce4 or ce5 coil will eventually gung up after a few weeks or months; if you are unable to get replacements easily, and for high vg, simple hardware: the type of thing you should get is an rda
Something like this:
$6.11 IGO-W Stainless Steel Rebuildable Dripping Atomizer - silver / 1.6ohm / adjustable resistance / double heating wires at FastTech - Worldwide Free Shipping
Rewick with cotton.