Hey there again Vappindaddy. Depending how low you are going to go, you have a few options. One of the better 30 amp continuous batteries is the VTC5 - but it's almost impossible to get a hold of. The VTC4 however is in stock in some places.
Sony 18650 VTC4 2100mAh 30a has them for about $11 each. I don't recommend going below a 0.2ohm build on any mech (but that is my own overly-cautious recommendation)
If you are planning on staying above say a 0.3ohm build, you could also use the Smsung 25R battery
18650 Samsung INR18650-25R 2500mAh High Discharge Flat Top <---- Illumination supply also has the LG HE2 battery which is another solid 20 amp continuous.
There are other options too, but I trust the two vendors above and use both of the batteries I mentioned regularly. The Samsungs are a great deal at less than $7 each - I have 6 of these batteries that I use in rotation in my Sigelei 100w. Great battery life too.
Finally, another good 20 amp battery is another from RTD vapor - the
AW IMR 18650 2200 mAh
I've been using AW batteries since I started vaping and all of the ones I have are still going strong. I trust the brand and the vendor. Just don't buy batteries from Amazon or Ebay, there are a lot of fakes out there.