This is a similar situation to rear panel connectors on a computer motherboard. Is it possible to fit the shield spring tabs on the back panel rather than use ones on the connector itself?
I'm thinking of the rear panel shields that are packed with new computer motherboards, they have a fixed overall outline to fit into the case but individual holes with tabs to fit the connector arrangement on the board.
I think that the option you are talking about is the one that will work best. Having the springs on the panel will facilitate mounting procedures. In addition this kind of connectors is rare and standard packages are preferred in our design.