Hi-o, since thc scientific hasn't dropped by to answer your questions and since I wrote the article that you're referring to, I hope I can clear up some of the confusion In my personal experience I never achieved much vapor with any Omicron at 19 watts but perhaps newer Omicron V4 are able to send out more power. I am able to achieve vapor at 19 watts on any box mod I have tried, and I do recall asking if it might be worth while to expand the stated operating range of the Hercules from 20-35 watts a little further, say 15-35 watts, because many users really enjoy the awesome flavors of lower wattage vaping. The lower the wattage, the more the entirety of the oil load and Herc chambers are heated, compared to higher wattages which tend to vaporize powerfully right at the rod. When used with appropriately shorter button pulses, higher wattage operation can solve excessively long cool down issues and leakage... I used to use my Herc like that but now i just leave it low and slurp terps...
Just wanted to state in case it wasn't known, that the wattage chart derived wattages are simply equated out using the
Ohm's Law calculator, because all previous SR versions were designed for the Persei operating at either 7.4V (any White rod) or 3.7V (the Black rod). That's why voltages were stated for those models- since the batteries inserted into the Persei determine the power and the correct rod must be used with those batteries for proper operation. With the newest Hercules, a rod of the same resistance (~0.8 ohms) as the Black rod, formerly designated for 3.7V is used. The higher resistance White rod from SR-71, -74, -74x may be used on a box mod, or more preferably the older SR series Black rod, or the current ".8" rod inside the "Hercules Oil Cartridge" with lower resistance may be used with a variable wattage box mod. Any of the rods will work, I've run them all. But for less voltage boosting, the lower resistance rods don't need as much voltage to reach your target wattage.
The different generations of Hercules, particular all SR-71 and onwards are very, very similar designs, and that's what I hoped to outline in my article were the minor revisions between each generation. The biggest changes were going from the SR-71 chamber to the SR-74; the deeper chamber of the SR-71 held more oil and allows 2 Ti coils to be used, the shorter upper chamber & rod placement of the SR-74x and 510 Herc works best with one coil only. And the next 'major' change was the 510 threading natively on all parts, and the 510 made out of a higher quality steel compared to all previous versions. Regarding pricing, all previous versions had a $99.99 MSRP for at least 1.5 years; I bought both my first two Hercs (first -74, then -71) for that price at retail stores. The price for the SR-71 listed at w9tech is only lowered now, if you read the item description, is because it's an unboxed bare unit without a wick, no instructions, and no tool. The SR-71, 74, and -74x all retailed for that hundred dollar price point, so there's really only a $30 increase going to the 510 threaded Herc; not a 60 dollar one.
The SR-71's press fit bottom post did allow for more power to be transmitted than the two piece spring loaded post that has been used since, the -71's side-clamping solid fitment means that lots of electrons can flow w/out resistance up through the post to the rod. Coupled with a 1.5 ohm rod, send 7.4V and you get a lot of power, up to 47 watts IIRC. As the battery voltage falls, the power output falls a bit too. The -71 was powerful so you'd use short pulses of power with it, continuously drawing to try and keep it in a good flavor zone. The SR-74 and later posts have a spring that pushes into the bottom of the rod and the parts of that post must fit together. It's not as solid of a connection which is why its rated for a maximum of 35 watts, and its White rods had higher resistance to deliver less power at 7.4V:
The reason the SR-74 didn't have as much power is due to it using the highest resistance (~2.3 ohm) rod. Again, this matters only on a Persei, and if you were using a
510-601 bottom adapter with a sufficiently capable box mod it could produce the exact same power as any other Hercules or rod. The next generation -74x dropped the resistance 0.2 ohms to give a small bump in power. With either the -74 or -74x you would use longer button pulses than the -71 to achieve the same vapor; or the same technique would produce a lot less vapor (but why would you want to use it that way). With a box mod its much much much easier to set the power level you want and get the vaping experience you want dialed in with the Herc via a combination of power level & pulse technique (or a low enough power level & dialed cool-down tech) that pulsing isn't crucial- let off the button a few seconds before you end your hit, and enjoy slurpin' terps.
I hope this helps! I better get back to packing up this box...