TOM fly to both Sal and Boa Vista from the UK.
Standard practice is to night-stop for both islands.
Depending on the rotation patterns a crew may stop for more than one night.
Historically, there and back flights have been rostered but these require morning departures to utilise maximum crew duty limitations and leave little or no flex for delays without use of discretion.
Boa Vista is, or at least was up until last year when I retired, a day only operation due to a lack of runway lighting and only has an NDB or visual approach available.
Other European operators night-stop their crews in the Canaries operating in effect a slip pattern eg TFS-SAL-TFS.
Hope this helps the original enquiry.