I think before you start messing with mech mods, you have to understand the relationships between resistance, voltage, current and power.
Here's an Ohm's law calculator. There are tons of them all over the internet.
http://www.ohmslawcalculator.com/ohms-law-calculator
A 0.5 Ohm build at 4.2 volts will draw 8.4 amps and produce a little more than 35 Watts. If your battery can handle at least 10 amps continuously, that should be OK (as long as the battery doesn't short to the bottom of the atty). That might be a good place to start until you get more experience with it.
Also a hybrid top cap mod is about the worst for a beginner just trying to get going. You might consider getting a mod with a 510 pin so you don't have to worry about that issue for now. You've got enough to think about at first.