Wiring two digi-set timers

Just putting finishing touches on my 32 Bantam SBC 871 blown alky 125" altered. I have a MSD 7AL3. I would like to use two digi-set timers to put timing back in after the initial hit on the line. I can set either timer in increments of 1/10th of a sec. up to what ever I want, mid run.
My question is, just how would I hook the timers to "undo"" the retards that I can put into the 7AL3?

 

I'll try and help with a suggestion. MSD offers so much stuff today it can be confusing which way to go is best. Without doing a lot of research and also using your existing ignition this is one way to go.
Purchase a MSD-8975 Digital Multi-Retard for about $265. Also purchase a MSD-8956 RPM Activated Window switch for about $92.
The 8975 can provide up to 4 retards, with the 8956 window switch you can put one or all of the retards back in within a desired RPM range. Just make sure the top RPM is higher than your expected top RPM.
I'm sure there are other ways, maybe a call to MSD would be your best coice to speed up the choice process.

If you can work with your existing ignition box and the retard feature is built in. Check to see if the retards are activated by adding or taking a ground away. Then you just have to wire it to address that. The RPM window switch could also be used for that.
Hope that helps some...............Blessings............Ron.