Yep, I very slightly enlarged the holes in the speaker’s rear plate. On my Tympanis, the hex-shaped Magnepan connectors are secured to the plate with rear-mounted hex nuts; aren’t yours?
Yes, I removed the stock insulator and put the Cardas black plastic mounting block in it’s place. It is the short "nubs" on the backside of the Cardas block that are slightly larger than the stock holes in the Maggie plate. Though the Cardas binding posts are usable without the Cardas mounting block, it’s advisable to install the block as it prevents the posts from spinning when tightened.
