how much to feed is down to you i feel ,you will know best .if they pair = they pair ,why worry that may the best motivation they need .how much training ? if flying well around home and previously raced , very little i would feel.placing the cock in once a week may or may not stop them pairing ,it was a suggestion to hopefully motivate a quick return. your first question also said you wanted to keep it simple, just send them ,if slow to trap , feed lighter etc etc .very best of luck.
ive put a little more thought into it ,and think maybe ,just send them , but have a cock in on return each Saturday .i bet by week 2 or 3 they will come home like rockets