OK, progress report on me and getting a V4.1 to perform. I've been fooling with coil resistance, low on the deck, up off the deck, micro coils and helical coils. Right now I'm running at 1.5 ohms with 32 gauge helical coils. Instant heat. They're up off the deck. I've played with the wicks, cellulose, after each tankful and think I finally got it right this time. I'm using it on a Vamo V2 in voltage mode with stacked 18350s and running 4.7 volts, or about 15 watts, and the vapor output, flavor and hit are all excellent.
I think the key, for me, was getting a minimal amount of wick in the channels. When I redid it today I trimmed and trimmed, a tiny bit at a time, until just a tiny amount of wick actually penetrated the channels. There was a little bit of a leak when it was first filled and on the Vamo, but that seems to have stopped. I did tighten the top cap just a little tighter and that may have curd the leak, I'm not sure though.
I will say that getting everything "just right" is a big PITA and takes a number of builds. Since this is my first RBA I'm not sure if that is expected with RBAs. I did install "cheese head" screws for the coils and I'm still waiting for SS flat washers to get here. The screws did help, but if I can install two washers per screw I think that will cure all the wire grabbing/coil pulling problems when installing the coils.