It's one thing to have a collection of antique perfume bottles, but a structured approach, or rather a methodical one, might be better if you think beforehand how you want to exhibit them.
If your collecting theme is of color and you buy only the one color, it would be difficult to have them on show all together.
Different colors of the same or similar size bottle would allow more flexibility in the displaying of them. Different sizes and colors even more so.
If you buy with a view to showing them in their best way, to friends and guests, you can be creative and artistic in your approach.
For instance, displaying in different levels of light enhances color and shade.
Placing them on or near a mirror gives a different effect to the display.
There are a variety of ways of displaying their artistic qualities , colors and designs which are only limited by our imagination.