I'll be making a car trip during the Grand Slam period, with stays at five hotels, and I want to be sure to follow the correct procedure to have each stay credited to DM.

All the hotels are in either the Choice or the Wyndham group. Is it correct that

(a) for all hotels in the Choice group, I present my Dividend Miles card at check-in, and

(b) for all hotels in the Wyndham group, I set my Wyndham reward preferences to credit stays to DM, and present the Wyndham card at check-in?