To do them properly, yes, the holes need enlarging, then there’s the issue with fixing holes being about 4mm out.
A new thicker baffle is probably the better/easier option on the rountuit list, I’ll prototype ply, then use Corian.
From the pictures, a B110 will fit, I’d like to get hands on before buying new ( Falcon), then there’s crossover issues.
All good fun, they sound great, although been put on the back burner since Art Moderne 8 arrived.