I get all those plastic trim pieces from my local ACE Hardware store. They have the plastic push pins in many varieties and sizes. They also have a variety of control panel plugs disguised as license plate plugs. They have the square tube end plugs (in different sizes) including the 1”. I can get the tank scale plastic tips in a variety of colors. Same goes for the wheel/axle end caps. Although I’ve only found red caps in 3/8”. But you could just get the push clips and reuse the white covers. The hardware store is MUCH cheaper than ordering online, you can get the quantity you need (Not 50 at a time) and there’s No shipping. I think I spent $9 on ALL the plastic pieces I needed
GLuck, J