New atomizers have primer on them that smells like machine oil - blow out, drip some liquid drops in, lets them soak down, vape mostly off without inhaling, blow out and repeat until inhaling tastes/smells ok. And atomizers can start to taste bad and need cleaning. And nothing I found would keep them from degrading.
Getting liquid in your mouth - nicotine is very peppery/burning taste. Atomizer + cartridge is a good way to get liquid in your mouth
Cartomizers - you need to use suitable juice (I find thin clear juices most suitable - I use 80PG/20VG). You need to fill to the stated capacity of the carto (figure 20-28 drops = 1ml). Then clean it up. Then settle it on all sides and ends (over 15-20 minutes is enough time for the thin juices I use). I use a plastic or delrin drip tip as a mouthpiece (easy to remove to add liquid or check if stuffing could use some juice). Keep cartos damp or you will singe them and get burnt bitter taste.
And fourth - don't put unsuitable ohms on a voltage. Whichever voltage you use, single coils with ohms .5 less than voltage will just be warm, and single coils 2.2 less than voltage will be very hot. You may want to stay in that range. If you are trying to use LR single coil cartos or atty on 6v, not gonna work well. Since you have a model you can also use dual coils - a 1.5ohm dual coil is two 3 ohm coils which I think is gonna singe on 6v. A 2.5 ohm dual coil is two 5 ohm coils which would be warm on 6v.