If you haven't already, then try e.g. 2.5mm ID spaced coil, like simple 24g kanthal 8 wraps. If you have wicking issues, then more cotton(as in bigger ID) isn't the answer, in contrary to popular belief, and spaced coils "wicks" better especially with thicker liquids as the heat is spread-out more over wet wick instead of concentrated over shorter area. I had same issue as you with contact-coils, and had to like you take semi-short draws at times. I use 95% VG DIY btw and when cold/not vaped for a while, I can have issues. Contact coils works, but needs lowered wattage imho(compared to spaced). I do like the lowered power-requirements and faster rampup of contact-coils though.
Loving my merlin btw
The smooth draw reminds me of my old kfl+ i've not used for years, but just with more airflow. Wide-open is the perfect slightly restricted DL draw for me. Thanks roxy and augvape.
...Tired of "cloudchasing" with high-powered dual-coil RDA/RTA builds and loving the single-coil RTA experience with reduced juice and battery consumption. A common evolution of many vapers I believe