Back when the Mets and Yankees played together at Shea in the mid 70's, doubleheaders were much more common. Looking it up on baseball-reference, there were 19 double headers at Shea in 1974 and 15 in 1975. The ideal these days would be zero. That means if the Cubs played all of their games at US Cellular, they would need to block out 162 days out of a possible 179 (taking 3 out for the all-star break) Day-night DH's for make-up would be a possiblity, but having each team play on the same day would be real problematic except in an emergency. I suspect the logistics would be much easier if they played one series a month in Milwaukee (18 games), making 144 dates work at the Cell would be much easier than 162.