I was never a fan of the Subtanks and the OCC coils, probably why mine are packed up and soon to be up for re-sale. You say you got the higher ohm coils and were not a fan of the tighter draw so that leads me to think you like sub-ohm and maybe more direct lung than mouth to lung hits. There are a lot of good
tanks out there for you, but most sub ohms are going to need higher wattage than your Istick is capable of.
I would recommend the Istick Pico 75 watt kit with the Melo 2 tank as you can get mod and tank for under $30 plus battery (charge with USB) and the eleaf coils are pretty good and inexpensive. The flavor on this tank is not as good as some others but its a decent vape and the tank doesn't leak. Con is the tank is a bit on the small side and you are limited to using small tanks on the regular Pico. There is also a Pico 25 which takes a bigger tank at a little higher price.
I recently got the IJoy Capo 100 kit and it is a nice Mod that can take 25 mm tanks. The Captain Mini that comes with it is a nice tank, dry for the most part but can still leak a little but good flavor and easy top fill, plus kit comes with a battery and has onboard USB charging. Con is the mod reads ohms off by up to .02 over what it should and no RBA section for the tank
Smok also has an excellent line of subohm tanks but the coils are a bit pricey. The Big Baby has an RBA section available. Slight leaking on these too
If you feel that you are ready to build your own coils then my favorite simple build tank is the OBS Engine Nano. Easy single coil build and no leaking. Pair this with your favorite Mod that is capable of 75 watts or more and can accept 25mm tanks and you will have a nice set-up . My favorite durable mod is the Smoant Battlestar dual 18650 batteries, onboard charging and pass through capable (Vape while charging)
Whatever you choose, look at the
reviews, watch you tube videos and decide what will work best for you. Welcome and good
vaping.