between D2 and Cloupor GT which one is good for newbie ?
   

Lower gage lower resistance.

wtf ? u use nickel with mech mod ?

The lower the wire gauge, the lower the resistance.
Example:
26 AWG Kanthal 5 wraps at 2.0mm = 0.56ohms
24 AWG Kanthal 5 wraps at 2.0mm = 0.38ohms

Thicker the wire, the less the resistance as it is more conductive.

You're using 24AWG Nickel???
JUNK IT.

Im not sure theres any mod or atty capable of using that.
Standard TC mods go as low as 0.05-0.1ohms.
So frankly speaking to reach a modest 0.1ohm using 24AWG Nickel = 16.5 Wraps at 3.0mm.(This is a big ass coil we're talking about)

One more thing, DONT use Nickel coils on any mod unless its a TC mod.
Nickel will degrade and release chemicals at low temperatures compared to Kanthal, so unless u want to poison yourself and or other people then stop immediately!

So again, junk that useless coil, unless its parts for making a bomb
Most common ones 24/30, 26/32
Yes u can make 24/26, but it will be ugly huge and imo juice absorption will be weak

can bro .. but dangerous ..

hey bro, i just obtained squonker too, a cheapo one though  . had it paired with the velocity with BF pin. works though. just dont over squonk till juice overflow hahaha. 
havn't tried squonking on the lowpro yet though i have one sitting around.
nickle what purity/grade? if ni200 better use TC bro.

dude...ni200 on mech? that's toxic yo
which shop told u this?!

plenty of coils around made from diff materials and not to mention diff builds
depends what u lookin for. flavor or clouds.
but only use ni200 on tc bro.