The fitting in time is definitely the most difficult. Transition and getting used to a home, other furballs and freedom is a huge change from the shelter and who knows what history he's got right!
I'd restrict him to some degree, even if it means keeping him on leads in the house for periods of time. Give him some down times, you sit on the sofa/chair while he lays at your feet. LAYS not sit, for intervals between 4 and 10 mins 2/3 times a day.
Reward him after with a small treat.
Transition...ahhhhh
Hey if all else fails bring him on over for a romp with Sadie LOL!
