I have mine in a 15' by 12' bedroom. I have so much stuff in there that there's not much room to maneuver. Quite a bit of stuff that doesn't pertain to building models.
May not be multiples of the same kit, so much, as it would be different re-issues of the same kit, with different wheels, decals, custom parts, etc....
My ratio there would probably be about 10%.
I try to do that, too, if I don't forget it. Some of us builders who are long in the tooth usually know which kit is being presented, but newcomers may not be aware, especially when it comes to kits such as Corvettes. Some of those year models were kitted by more than one company. '57 Chevies are another example.
I like that one. Wouldn't mind having hidden headlights for my MPC, when I get ready to build it. The AMT I have is not a complete kit. Would either the AMT '67 or AMT '70 chassis work on that one?
And you could swap the engine with the V-8, because the Pacer was available with the 304. I test drove one back in the day that had an AMC 360 stuffed into it.
Sometimes, it's like throwing dice. You don'e know what will turn up. I've used the directions on the cans before, only to end up dunking the project in the purple pond! At times, I have used my own willy-nilly method and it came out looking pretty good!!
Trial, and error!!
By posting what you're working on, the GURU builders that hang about on this site can better be able to give pointers on certain aspects of the build process, if you are hitting any walls. I know I've been helped a lot around here, and I've been slappin' 'em together since the 60's!!!
By The Way....welcome to the forum!!