In theory this is all you need along with four Continental type
injectors. It functions almost exactly like my new carb design.

The hose  barb on the right is connected to the intake
manifold behind the slide throttle. The regulated pressure
increase with intake manifold pressure increases.

How much it changes is a subject of an email question I sent
to TWM.

If it increases 15 psi as the manifold pressure increase 15 psi
we are home free. The only real fly in the ointment is
it does not start at zero pressure. I'll have to give that
some thought.

The problem is leaning the engine as this pressure regulator
has a screw to set the mixture rather than a lever.

However it could be mounted on the instrument panel
with a knob that you turn.

You start the engine the same way. Turn the engine over with the
starter and then turn on the fuel pump. The accelerator pump
is the same device that I use. A pancake air cylinder mounted
on the throttle knob will send a shot of high pressure air
to the regulator temporarily increasing the mixture. This device
can also be used for starting the engine.