I am installing a 5 ton heat pump system in my home this year. What size should I make my main trunk size?

I would like to have 4 take offs on the first floor. I am going to have to also run some duct upstairs so that I can add 3 more take offs. Can anyone tell me how to correctly size this...Main trunk for 4 takeoffs, duct going upstairs and 3 takeoffs up stairs. I would like to try and keep 3 tons downstairs and 2 tons upstairs. Thanks