Your REALLY REALLY on the right track! Good job!
A P30 can run an OBD1 B18C1 with a Hondata chip. It will need wires run for the IAB, but it will work as if it was a P72. If you won't be putting the Hondata chip in right away, go with the P72 as it will run the motor correctly from the factory. The B18C1 is from a GSR; maybe that can help further your searching, if you didn't know already.
Bag the vtec controller though. Hondata is a much more beneficial solution. It also has dataloging so you can connect a laptop to your ecu and read the inputs from every sensor, making problems very easy to diagnose.
Your best bet is to convert the motor to OBD1, which would entail replacing the distributor and mayyybe some other stuff (sorry I don't know exactly, but it's possible!). Hondata works with OBD1 only. It's also easier to tune, and it's the native OBD spec of your chassis. Making the emissions/legal front a little more legit.
If you want a few extra bucks and want to shed a lb or 2, sell the MSD. Just not necessary.
