Usually the surge return is just threaded through the top of the surge tank, there's no way for it to siphon the fuel back to the main tank.

(Is see you've changed the line drawing to include the surge over flow/return line)

The setup I ran on my series 2 RX-7 (ported 13b, To4e, 8 x 1000cc injectors).
2 x Bosch 010's inline (there was no intank pump) as lift pumps feeding a 4 litre swirl pot (mounted under bonnet), the return line to the main tank was tapped into the top of the swirl pot.
The High pressure side consisted of 2 x Bosch 979's, 1 feeding the primary injector rail, the second feeding the secondary injector rail. Both pressure regulator returns fed back in to the top of the swirl pot.

Set up was good for 440hp atw @ 1.1 bar, never ever had any surge issues.

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[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]