Base is VIE for all new hires.
Fleet allocation is done at random. Has nothing to do with your experience. They put you there where they need you.
You might think you will fly Fokker, however...
Presently we receive a lot of F100's. Many Dash8 captains switch to the F100, Dash8 copilots become captain on the Dash so a lot of newcomers become copilot on the Dash8.
CRJ fleet is stable at the moment so newcomers go mainly to Fokker and Dash.