There's no shortage of things to learn about vaping now. There weren't as many choices when I started, but even then it was confusing enough. Then I upgraded my setup a year ago and found that most of what I'd learned was now useless and I had to start all over again. It looks like you're working your way through the essential bits, so here's another one for you:
Batteries - There are only four manufacturers that make batteries that are suitable for vaping. They're Samsung, LG, Sony/Murata, and Sanyo/Panasonic. Anyone else selling vaping batteries is called a "rewrapper". They either bought their batteries from one of those four and put their own branding on it, or they're using a battery that really isn't suitable (or safe, for that matter). Most buy from the legit manufacturers, but even then the batteries they buy are usually the ones that didn't pass the quality assurance tests to be sold under the manufacturer's own name. Worse still, the rewrappers often give inaccurate specs for their batteries. To complicate matters, even if you find out what battery a rewrapper is rewrapping, they can change it at any time so you can never be sure.
Mooch, our local battery guru, has tested a lot of batteries. He found the Efest 3000mAh 35A battery to be a 20A battery (although as I've just said, that could change at any time). A 20A CDR battery isn't bad. On a regulated mod, you should be OK up to about 60 W per battery with it.
This link will tell you how to calculate the maximum wattage you should use depending on your battery's CDR:
Calculating battery current draw for a regulated mod | E-Cigarette Forum
In the future, I'd recommend sticking to Mooch's recommended batteries. He makes a very handy chart of good vaping batteries, but sadly he's updating it at the moment and it's not available. When it's ready it'll be here:
Mooch's Recommended Batteries | E-Cigarette Forum
Off hand, if you're staying below 50 watts or so per battery some of the top choices are:
- Samsung 30Q
- Samsung 25R
- LG HG2
- Sony VTC6
It's also important to stick to a reliable vendor because there are a lot of counterfeit batteries about. Never buy batteries from Amazon or eBay. Mooch's chart has a list of good vendors on it, which will be helpful when it's back up but doesn't do much for you at the moment. There aren't any Canadian vendors on it and experiences importing batteries have been mixed. A lot of people have bought numerous batteries with no problems at all, while others have had nightmare experiences with customs. My own preference is to avoid potential customs pitfalls. I've had good experiences with Dashvapes.
While MTL usually involves higher resistances, there are a lot of contributing factors. Airflow is one, and, as Anna mentioned, your power setting is another. The Nautilus 2 that was mentioned has coils ranging from 0.7 to 1.8 ohms. They're all MTL, and people's preferences are all over the place. If it works for you, you're doing great.
There's no need to apologize for questions. We're all here because we're happy to help.