Not to answer your questions directly, but Paul Hammant has written a bunch about this over the years:
http://paulhammant.com/2013/04/05/what-is-trunk-based-develo...
http://paulhammant.com/2013/05/06/googles-scaled-trunk-based...
http://paulhammant.com/2014/04/03/microsofts-trunk-based-dev...
http://paulhammant.com/2014/01/06/googlers-subset-their-trun...