While you can make more money grinding VIP work like Head Hunter, then do a contact mission, then do Sightseer... It gets boring. So to switch things up I decided to put together a play list of Martin missions... 12 missions that are simple to do solo ... easy to do from the Deluxo... the trick is to finish each mission just over 4 minutes into each mission (like 4 minutes and 5 seconds from when the banner drops off screen and the mission starts). On Defender I screwed up and finished at 7 minutes and 45 seconds and lost a couple thousand dollars (always finish just over 4, 6, 8, 10, 12 or 15 minutes as that is when the payouts change)... I should have taken about 15 to 20 seconds longer to "meet Martin's contact" at the airport (should have waited 15 to 20 seconds before entering the yellow circle to trigger the contact). If you were to add Head Hunter before and again after what I did... you can add another $40,000+ to the total and finish in around and hour and twenty minutes.
PS4 go to Rockstar Social Club and search playlists for MartinMissions