I had leaking issues with my crown and my Herakles. I haven't had a single problem with my tfv4. You and jerus both got me into wanting an rta, it's like a mix between rdas and sub ohms. I really want one. I heard the billow v2 and the Griffin are really good rtas. I guess I never really cared for building an rda because I didn't like the fact that I would constantly have to drip it. It just seems like a pain in the ass.
Start with the RDA because otherwise you'll end up doing a lot more work and wasting a lot more cotton and juice on failures. Once you understand the basics then you can jump to RTAs, but I'd suggest just grabbing the TFV4 dual coil RBA to start, it's like $8 and will teach you the same basic principals and once you get that then jump to RTAs.. at least that'd be my cost effective/stress effective suggestion.
And I may know a decent bit, but I'm not an advanced coil builder is what I was getting at, I can't make Aliens, I still screw up my claptons, and I haven't even tried Staples yet... so the "advanced builds" are out of my wheel house.
I'm sticking to Kanthal mainly now, but just because the SS that I use (and love for what I use it for) comes in as too low resistance (26g cored fused claptons come in at .09Ω, a bit lower than I like). But I have a healthy supply of various gauge 316 SS and a nearly full gambit of Kanthal A1.
As for finding coilbuilding tutorials, there's so many good ones I'd just type it into youtube and check it out. What was linked will be great to start, but try typing Parallel coils into google, Zipper, Twisted, Clapton, Fused Clapton, Alien, Staple, Framed Staple, Helix, Chain Link... lots of types and even more guides on how to do them.