Wasn´t sure if this one or the mecha one would be better for my question...either way, here I go.

I´m trying to rebuilt Metal Gear Rex in Lego.
Started just for fun without a plan, but the headpart turned out so good that I decided to make a bigger project out of it.

My three questions being:

Would anybody happen to have Metal Gear Rex as a figurine and be so helpfull to take some very detailed photos? Especially of the middle area which is hidden in pretty much ALL the photos you can find.

b) Does anybody here have experience with Lego-Mechas (this is my first one)? And if so, my biggest problem at this point is the maneuverability of the head. How do I built the "neck"-part, able to move up and down, right and left, all rather freely? My only concept so far turned out to be far too big for the model and looked ridiculous.

3. The head turned out fantastic but also already took up big parts of my arsenal...is there any place where I can get literal SHITTONS of grey parts for very cheap? Cheaper then pick-a-brick, that is, because I can barely afford that one.

Thanks in advance.