Buschur double pumper fuel system vacuum switch?

[1gDSM4g63]

I bought a Buschur double pumper fuel system, but I have a general question. Should I use the vacuum switch as a relay switch replacement for the second pump or should I still use a second relay switch and the vacuum switch for the second pump??

 

[twicks69]

I have not done this before, but I would suggest using a relay and then the Hobbs switch. The Hobbs switch will last longer if you take the load off of it by using a second relay switch.