There is no accepted two-breed recipe that produces a Maine Coon. It developed as a natural domestic breed rather than being established by a recent planned cross between two named pedigree breeds. Stories involving raccoons or wild cats are not a sound explanation of its ancestry. If somebody advertises a particular cross as a purebred Maine Coon, ask for registration and parentage documents rather than relying on the description. Crossbred cats can make excellent companions, but their label should accurately describe what is known.
For your home, ancestry also does not guarantee exact adult dimensions or personality. Buy essential equipment using current measurements and realistic allowance for growth. Record those measurements over time, especially when a youngster begins to look cramped in its carrier, sleeping platform or litter tray. A seller describing one parent as another breed is describing a cross, even when the kitten strongly resembles a Maine Coon.
For product comparisons alongside this advice, see Velvet Nest and Sterling Court litter tray. The details below explain their sizes and uses.
Further reading: gccfcats.org; pdsa.org.uk.
Velvet Nest
Sterling Court litter tray
Taj-MeowHall