I just build a mod using the Madvapes regulator and meter (I put it into my Motorola VV mod...I've been abusing hard it for days and it hasn't broke yet)...those regulators get hot so I would (if you have the room) use a bigger heat sink than just the metallic tab on the circuit board (I used a thin 1"x1/2" stainless steel shim I cut out of a piece of something I had lyin' around), mount the regulator as per instructions then carefully slide your shim between the back of the black IC chip and the board...heat kills and this will go a long way to making your hard work last. As far as the meter goes, if you're looking at the face of the meter (pins facing down) the furthest left pin is the neg and the one next to it is pos (the rest of the pins aren't used)...you can just attach it across your atty connections (optional, intercept the pos wire (or neg, doesn't matter) with a small tactile switch)...that way you can slightly unscrew your atty, (press the tact switch if you put it in), adjust your volts, screw the atty back in and ta da...*the meter doesn't glow every time you press the fire button if you put the tact switch in, or you can not switch it if you like all that metery goodness, it's your mod, be proud of it take pics and show us when you're done...best of luck.
Just wanted to add, stainless isn't the best thermal conductor to dissipate heat, if you have any copper or aluminium even better, just make sure it's perfectly flat (don't just beat a penny with a hammer, you want maximum contact with the back of that regulator)...I just used it cause my tin snips and the what ever it was was lyin' right there and I'm pathetically lazy...