Princ Res Disposition - only one spouse on title

Do you enter the sale to S3 for each spouse due to beneficial ownership? If yes what % ? 50/50 ?

scroll down to the bottom of the S3. there’s a section specifically for principal residence entry. It has % allocation there

only one spouse on title.
PR for both spouses.
I dont know if I have to report for both

Only the ones who are deemed to have sold their share.