Heater plumbing

[Flat Eric]

Westfield heater has input/outputs for 16mm coolant hose.

My V8 waterpump has input for 19mm hose.

Obviously need to reduce hose.

Got me thinking. Does it make a difference where I reduce it. If I have 19mm hoses to/from heater.

Does this:

1) increase the flow through heater matrix

2) increases water capacity, obviously to a negligible level

or

1) water is cooled more efficiently via main rad therefore no benefit?

2) wider hose therefore velocity of water slower? (is this negative or a positive thing?)

3) gauge of pipe within heater matrix governs speed?

4) obviously any gain is reliant on heater fan actually being turned on, which generally it is not.

Any thoughts?