I used to put about 90% of my spend on by BA AMEX and and 10% on the Platinum and got offered Centurion a couple of years ago so I do not think it matters what card the spend goes on.
I don't think anything can garuntee an invite, infact I am sure I have read that they are not handing out invites at the moment as they have their quota of members. Maybe RM can shed some more light on that?