Customs Help.
 

Just starting up on my first custom, Trying to turn my ML Pyro into habit of a spin on Firefly from "The Batman" loved his design.
I was just wondering if this stuff is any good?
Green Stuff 36" Kneadatite Blue Yellow Sculpting Putty Warhammer | eBay

And what would be the best way to pop off this guys head lol! Thank you! And I'm sorry if I'm asking stuff that's been asked before I looked around a bit but couldn't find anything that pertained for just these guys.

It works, but if you live in the States, the best thing there is, apparently is Aves Apoxie sculpt Welcome to Aves Studio
As for poping the head, just submerge it in hot water for about 40 seconds and pop it out (I normally stick half a glass of water for around 2 minutes in the microwave, to let it "boil", then I stick the figure/part in). Other way, is using a hair dryer over the part, you just let it heat/soften enough to pop it out (like a minute or so)

I have to disagree w/ Metalalchemist I use green stuff, and that stuff is awesome. Then again I've never tried Aves, but I've heard that it's a pain because both parts A, and B are white so you don't know when it's fully mixed.