The Tribute Belt (well, the one that wasn't a Hero Net exclusive) is the "New" Rider 1 version anyway (that has a red belt part instead of white.) The one you have can either be painted white, or I'd guess you'll probably rig up some kind of new belt with just the buckle part from the actual toy, cuz the red plastic belts that are on the cheapo ones are pretty restrictive.
If you're thinking of making a more classic "Sakurajima"-style Rider 1, the colors on the helmet there are about right. I can't really tell from the lighting, but the top of the mask should be a slightly darker shade of green than the bottom (this is true of the real NEXTy mask too.) The gloves, boots and chest armor are the same color green as the bottom of the mask, or just about. And as you mentioned, there's no stripes on the original suit.