Don't have a tugboat but with cotton don't thread it through the coil really tight , it should have some minor play . With Rayon (since it tends to shrink and not expand like cotton) i thread it through the coil a little more snug and tuck both ends down into the well on an RDA like the Magma.
It's really just a matter of trial and error and having the coil made at the correct ohm's , lower ohm's with a lot of airflow will usually produce thicker clouds. What your juice makeup is , is also a factor , more VG = more clouds.
Oh, OK , i see you use max VG already , have you tried dual coils , try that if you can but what many are trying to say on here is that a fancy coil does not instantly equate to far more clouds or a better vape .
You may also want to try 26 or 28 gauge for faster heat up which will promote better cloud production , i know you have an iPV II but at what setting and is your coil heating up fast enough to get the most out of your RDA.
If your coil is taking a few seconds to heat up then you will need to hold down the firing button longer to compensate for that lost time , a coil that glows instantly will produce vapor faster and therefor seem to produce clouds quicker when you press the fire button , hit it and release like most folks do
