I'd personally say (never used a lava tube, but seem some awesome vid
reviews) that you're always safe with 2ohm and 3 ohm boges. That would be the SR and the LR. They're inexpensive (esp at crystalclearvaping, if you buy 15 at a time.. like $20), last ages, and really perform well.
I think this will really really help you out. You might want to watch it a few x. Its Phil Busardo's very in depth review of the Lava tube (called something else, but its just rebranded... definitely the lt). He goes into specifics on Reg and mini size, and fires 1.25, 1.5, 1.75, 2.0, 3.0, and 4.0 ohm cartos/attys at all the different voltages, and shows you exactly how high the lt will go, voltage wise, on each before it cuts you off at the 2.5 amp limit. VERY useful. I'm geing a Vision Tox vv... super similar to the LT in how it works with the vv, so I was very interested. Plus, Phil's got some fab
reviews on popular cartos, like boge, resurrector, etc. If you're newish to cartos, it'll really save you a ton of experimentation. Plus, that way, you know before you spend money on cartos if they're high resistance enough to get you to your sweet spot in voltage, before the LT holds you back at the 2.5 amps....
Here's the LT review...
Taste Your Juice | VZ VV Tube Mod (AKA Lavatube) Full vs. Mini Vaping Zone
Here's the cartos section...
Taste Your Juice | Cartos & Attys
And all his reviews, handy price charts for juice etc are all avail at
TasteYourJuice.com. I love Phil's reviews as he goes in depth on all the tech specs, and tests things I'd never even consider. He tends to like the same things I do, so works out well. GrimmGreen and Scott also do fantastic ones.