Probable a well known method but i had someone ask so here is what i do

1 design and keep current my "optimal" starbase upgrade constructor (because using the default sucks)

2 Create a Rally point (or 2) that is centrally/optimally located

3) Set 1 or more shipyards to build and send my constructor to RP(s)

4) First one arrives at RP , set it guard so it does not keep bugging you, additional ships will auto stack/guard up to your logistics limit , at which point next first in stack must be set to guard.

5) Once i have good pile of constructors at the RP, move each fleet stack by one of manually cancel guard

6) open SB #1 hit request const. as  cycle to next SB and repeat as needed up to the limit of total pre built constructors.

Obviously early on it is easier and always more efficient to manually dispatch constructors as they come off the line but mid to late game its much less micro intensive.

If there was a way to make ships go to a RP and just sit idle it would be even better

  OR EVEN BETTER^2 let us pick the default constructor the the request button uses  >>>> SD listening ??? <<<