>>10907113I think that red dome is in one of the GS sets, though I'm not sure in which one. I don't have any GS.
I use parts I like and I mostly pick up parts on Bricklink. My process is: I want to buy a specific part/set/minifigure from some store. I get that and then look through the entire store for other "cool" and interesting things I think I might need or want for later projects. Bubble canopies (in any/most colors) are always on the list.
Other than that I buy parts in bulk for decent prices.
Build with what you have, and whatever you come across. Mix things up and have fun.
