How to make worker carry multiple resources?

I want to make a rather simple (?) change: I would like Probes (or other workers) to be able to carry multiple minerals at the same time. I would expect the probe to:

approach the mineral field
gather minerals
gather minerals again
... and again...
and then carry it back to the base

Originally I thought it is a simple data change of the worker: I thought it could be simple as changing the behavior Carry Mineral Field Minerals->(Basic) Stats; Maximum Stack Count from 1 to 5. Unfortunately, as soon as a probe gathers the minerals, it automatically returns.

After giving it more thought I figured there may be some built-in trigger, checking if the worker is already carrying minerals - and if that is so - issuing a "Return" order. Since then I have been digging into available triggers, scripts, unpacking Liberty and Swarm mods, but so far - I could find nothing.

Any ideas? Pointers?

I am new to modding and I don't plan to do anything big. Just want to hack this for some experimentation...

I know how to increase gather time and how to make probe just carry more minerals in a single patch... but I want to specifically make the probe retrigger the gathering multiple times before it returns (and add some delay in between)

Also, I don't care what happens when mixing minerals with gas or any other resource.