There are a lot of variables that govern how well (or poorly) these things work, and its a balancing act to find what combination you like. And a lot of 'general rules' that developed, based on experience and/or analysis. That's how the 1.8 and 2.4 (and 3-ohm)became popular values, as some found that a reasonable combination, and word spread. Don't forget dual-coils (two 3-ohm coils in parallel = 1.5 ohm). Two coils gives more area than one--more surface area/more vapor. Two coils consume more amps than one--less battery life. How happy will your battery (eGo?) be with these (pushing it so hard that it starts to cook itself?)? I've also found with some ejuices that I can get more flavor/satisfaction from one combination, and more vapor (but less flavor, maybe scorched-tasting) from another. Also, can the wick feed the ejuice fast enough, to prevent dry/scorched hits?
So, am I looking for more vapor? more flavor? battery that lasts all day on one charge? Those are only a few of the pieces I need to balance. Other things like how much ejuice would this burn through, will my battery live long enough for 500 charges, will I have to top-up my cartos too often, which worksbest the way I want it to, with my 'tobacco' ejuice? my 'coffee' ejuice? my 'BikerBobs special brew' ejuice? I'm not sure I'd go for 'lots of vapor, battery that needs charging every hour, just a hint of flavor, sometimes burnt', but some would.
Sometimes its quicker/cheaper to ask/research these things. Sometimes its quicker/cheaper just to try it for yourself. Your mileage may vary.
So, am I looking for more vapor? more flavor? battery that lasts all day on one charge? Those are only a few of the pieces I need to balance. Other things like how much ejuice would this burn through, will my battery live long enough for 500 charges, will I have to top-up my cartos too often, which works
Sometimes its quicker/cheaper to ask/research these things. Sometimes its quicker/cheaper just to try it for yourself. Your mileage may vary.