We decided to use the original footprint of the building, and that a good size workroom was more important than the display area. It's more storage/display as I plan on having more of a traveling show, with most info on the internet. I'll be open by appointment only - for those traveling through that want to see the machines in person. I don't want my insurance rates to go through the roof either!
I know that no matter how much room I have, I'll fill it up. So by staying small, it helps to keep a lid on things so I don't go from collecting to providing a shelter for all unwanted machines - or even slip over into hoarding. And since the bulk of my collection (in item count, not volumn) is my attachment collection, that takes up a lot less room. It's nice to have one machine that the attachments fit, it's not needed to have one machine for each set of attachments (since I have about 10 unique sets for New Home VS machines).
I do want to have one complete period appropriate set and manual for my Singer machines, and I'd already have that if I'd quit buying Singer machines!