I`ll fit a custom 7 gal alloy tank for a capri 2.8i soon.

The fuel pick up pipe dia in the tank is 8mm. As I know the bosch fuel pump input is 15mm.
I`m planning to use a 15-12mm and a 12-8mm reducers to connect them.
I`m going to mount the pump as close as possible to the tank but I was told the pump might struggle to pick up the fuel.

What do you think about this?

(I could return the tank to the manufacturer to enlarge the pick up pipe, but I`d avoid this if possible that way mentioned above.)