I have a vertical smoker and I use rib racks to maximize space so I can get at least 30 full racks of ribs.
I see no difference in smoke flavor between my racked rib and my non-racked unless I allow them to touch each other.
To answer your question is that it shouldn't matter unless they wind up touching each other. Where they contact each other the smoke will be diminished...
Humphrey's DownEast Beast W/BBQ Guru