@KAB - Morning.
Righty sparky: First off, what wire were the Claptons made of that you were putting in? Kanth Claptons are not a good idea for a mech. Claptons unless made from minimal SS are generally pointless on a mech as there is way too much metal to heat up. If you didn't realise that, you do now.
Next, you do know how a mech works? Every time you use it, every squeeze of the switch the available power decreases, thus the power output goes down. All you have is a battery, no gubbins or widgets, just a battery. Think of it like a water barrel for watering your garden, every time you fill the watering can there is less water available, until you refill the barrel.
Will be well worth your time using a lower resistance wire like the Nichrome the now. dual coil 6/7 wraps and a 2.5mm inner should be useful and you should get a fair few hours of tooting.
I had my Dripbox with me on saturday and got thro' all day without a battery change. I had a single 0.45 ohm coil in the Hadaly and had plenty tasty vape.
Aye, yir right a regulated gadget will keep a certain set power output until the cells lose charge, so for you I think a chipped thingy would be peachy and mostly what you are after. The V2 dripbox could be a useful investment but do get a good atty to go with it as the one that comes with it it beyond gash. From fast tech you can get a lovely Hadlay clone for ~£6 for flavour and for the same price a BF Kennedy for cloudy days.