I never tried the glove thing on the couples (neither the green, nor the red one). Think I'm going to do it on my next generation.
About baby boost, the only time I applied it prior to the honeymoon was a complete disaster. I don't know if that was a coincidence, but they had very serious problems in having babies. They didn't argue so much, but they kissed and nothing.
My luck was that they adopted 2 kids, then I could go to 6 kids at the end.
The only times I had twins were when I had them try making a baby once. If they had a baby, good - if don't, I'd get the doctor's appointment and see the one who needed baby boost.
As I'm still waiting for my triplets to come, that's a concern, I mean, I have to make them have babies (by the thousands! *laughs*)
About the compatibility thing, I must confess I rarely take a look to see if the match - I see the peep face, likes and dislikes and see if I think they would be a nice couple. I think I'm really sentimental regarding my peeps sentimental life.
I had only elated couples so far.