I would call FITECH and look at Holley EFI (both companies) for dual throttle bodies, both dry and wet (with injectors inside of them).
I bought and installed a Holley dual dry throttle body system for one of my local customers that wanted it for his 571 C.I. street hemi motor, I bought a KB Stage 5 dual inline intake that is made mainly for EFI systems, I can't remember who I had set that intake up for the direct port injectors That motor made 799.6 HP at 6500 RPM and more torque than HP, good vacuum at idle 900RPM and it idled like your grandpa motorhome motor home did
Throttle injectors supposedly don't like dual plane intakes like yours The direct port systems don't know what type of intake you're using, I would go with the direct port injectors on your intake and run both throttle bodies hook up 1 to 1 That type system is a lot more tunable also
IHTHs