Ignition Switch Problem / MSD Ign.

I need suggestions. 1969 Valiant. I removed all the stock ignition wires and equipment and installed MSD, everything. The FORD/GM side of my brain was thinking to tap into the blue/white ("on" position) wire out of the ingintion switch to power the MSD. What I discovered after 2 hours of scratching my head is this. If the key is in the on (not acc.) position the blue/white wire is hot. As you turm the key to the start position the yellow becomes hot feeded the starter safety relay and at the same time the blue/white wire has no power while cranking. Thus I had power the the MSD in the "on" position but, no spark (power to the MSD) in the cranking position :wack:. It was driving me nuts. I looked for a wire that was hot in both the "on" and "start" position. Notta! Here's what I'm thiniking......

Install a relay that is normaly open. The relay is triggered by the yellow "start" wire while in the start position the relay contacts close and provide power the the switched bus bar (MSD brain & accessories) while cranking. When the key is release back to the "on" position. THe relay contacts open and the power is sent to the switch bus bar via the blue/white wire. There will be a very breif moment between the relays but, I don't think it will effect anything. What are your thoughs or any other solutions you might suggest. Thank you in advance.

Brad :prayer: