Set up a playpen in the corner of the main play area. When he cries pop him in, say "no crying" and leave him till he stops. If he doesn't stop, every 10min or so simply remind him "when you stop crying you can come out". As soon as he stops take him out...as soon as he starts up again pop him back. Keep calm and simply restate "no crying".

Could the fact that you are trying so many different ways to please him be what is making it longer for him to settle in?

Stop trying? Lol...just leave him to figure out that this is how it is now. If he is crying all the time with you standing on your head trying to please him then he might as well cry with you not killing yourself trying to find a magic solution.