For what it is worth on a slightly different system (Holley Projection) on a 350, I had to set the pre-fueling to about 150%.
That is the equivalent of the "squirt" that you get from pumping the gas pedal before a cold start. The goal is to pre-wet the intake walls and get some aerosol fuel into the intake before cranking it. I suspect that the long (and mismatched) runners on the 235 intake will require a similar value.
