In all honesty, it is hard for me to get excited about the Golden Century stuff because I didn't design any of it. I just did slightly updated version of existing mechs and Brent Evans did the designs for the Woodsman and Wakazashi (I just inked them). I would be more interested if they made minis for my Operation Klondike drawings. They were also refits of existing mechs, but I was allowed to make more interesting changes and I think the updates made the mechs look better.
Details are just the final touch so always be sure that you have a strong basic drawing before you start adding details. Details are good for indicating the scale of your mech and also indicate if the mech is made with modern tech or future tech. Things like rivets and hoses should only be added to retro stuff. I like to look at real vehicles and factories for detail ideas.