I do not have mine plumbed that way but I would try using the EGR port and see how well it works.
I have not had any time to work on my trucks for a few months now. When I do get freed up there is several things I want to try with my Webers and different set ups.
I have a 1986 720 king cab that I have had a new Pierce Manifolds Weber DGEV on since 2011 just after I bought the truck. I have a 1984 720 King Cab that I have a rebuilt Z20 for and it will get a used Weber DGEV installed when the Z20 is in the 84. I also have my 1966 520 that I have a rebuilt L20B and a rebuilt automatic trans in that will get a new Carbs Unlimited Weber DGEV when I get the exhaust and wiring done.
I have run Weber DGEVs on my Datsun/Nissans since the early 70s.