KEF 104 grill shape

I recently acquired a pair of kef 104aB. The model had foamgrills that are no longer available as they have all crumbled to dust since the 70s. I have some generic foam coming, but it looks like just attaching it to the existing velcro hook won't work be cause the woofer surrounds protrude from their baskets. Does anyone remember how the grills worked on these? Thanks!