Question on reducing pluming

[Hammerleaf]

I'm setting up a new tank and my eternal pump has a 1" output. The returns in my overflow are 3/4". My question is where I should reduce the pluming. Should I reduce if closer to the pump, or closer to the tank?

 

[USC-fan]

I would stop reduce it to after you split the return. I would run the bigger pipe as far as you can.