I just got the tfv4 quad coils which is a .15 resistance, and I'm using the smok x cube 2. The only battery's you could get on the site that I got it from were the 25r's are they safe to use or should I get the vct5's? If they are okay just not at a high wattage,what's the highest I should use it at. Thank you guys for any help I get.