Hey, I've also got the new iPV D2 and run a Tugboat RDA. I've made a handful of builds which I'll briefly cover.
First was a 6 wrap 3mm ID single contact coil. This did surprisingly well for my first Ti build and I was pretty impressed with TC in general, being my first TC build too. Ohm'd at about .25 and performed nicely at only 15J.
Second was a parallel 5 wrap 3mm ID single contact coil. I wanted to try less resistance so I built a parallel (I like running single coils over dual coils usually.) It ohm'd at about .093 which was fun. Unfortunately, I felt like this one did poorly and the flavor never was quite right, sometimes even bad. I gave up on it pretty quickly, after probably 5mL through it.
What I'm running now and loving, is a twisted 6 wrap on 3mm ID single spaced coil. I haven;t really ran much spaced coils, but after reading a lot about it, I decided to give it a try. I think the spacing allows the APV to regulate temp better as well as gives a more consistent vape with less gumming. Here's a picture right after I build it with some clear juice. Nevermind the bit of sloppyness at the right side...
Anyway, I'm loving TC and Ti wire. I would say it's slightly more springy than 24ga Kanthal, really not bad at all. Not so sure the Tugboat is the best, but it sure works for me.
