It sounds to me like you have multiple issues.

1) The excessive fuel consumption and dieseling may be due to too much pressure for the carburetor to handle on the #4 setting.

2) The lack of power at higher rpms or under load on the #3.5 setting sounds like the main metering jets aren't large enough for your engine or the choke isn't opening completely. Look at your tailpipe to see if it's sooty or brown. If it's brownish white, your jets are too small..... sooty means your jets are too large, or the choke isn't opening all the way. A tannish brown is just right. Check the choke action with the engine fully warm and make sure it's completely open.

I use a Carter P4010 rotary vane electric pump to feed the Weber 32/36 on my 2.0L Mighty Max. It's a loud pump, so if you use one, mount it to the frame rail and with rubber grommets to isolate it a bit.

I don't use a regulator, although I think the pump is just a little strong for the 32/36 because I get a little dieseling if the rpms aren't all the way down to dead-low idle when I shut it off. I find if I blip the throttle just before shut-down, it doesn't diesel at all. I could also install a regulator, but it doesn't happen often enough to concern me.

I use a standard automotive type relay as a pump relay and trigger it with the coil B+ post - because that is only hot when the ignition switch is in the RUN or START position.... main power to the pump goes from the battery to the relay to the pump.

Someday, I'll wire in the oil pressure cutoff switch that kills the fuel pump when the engine oil pressure drops below 7psi - even though the ignition switch is in the RUN or START position. For starting with such an arrangement, you can rely on the fuel contained within the carburetor bowl - or wire an override momentary switch that you push and hold while cranking until you get oil pressure showing.

Others will likely have some different ideas for you..... there's no one perfect way - you have to find what works for you and your engine.

Frank