The 12v pumps that have worked best for us are from older Mercedes diesel cars; mid to late 80's. The rides we do are mostly street or resto rods so the battery is moved to under hood and the pump is mounted in the old battery box. Larger 5/16 or 3/8 rigid line is run from pump to firewall then reduced to 1/4 for the wiper motor connection. The pump is a long way to behind the spare tire in a Mercedes and there are numerous vacuum controls so the pump has enough volume for AD wipers. I can't vouch for other vacuum pumps but a reservoir is a good plan for any.
