Welcome! Here are the website rules, as well as some tips for using this forum.
Decreasing pipe sizes on zones
you are good with the numbers . Yes , I mean connecting the main to the circulator on the supply . Usually less than 2 feet on a replacement .
We rarely see 3/4 takeoffs to the convectors , even on an 1 1/4 inch zone .
Thanks again Brad for the insight and the math . I really appreciate it .