I use a dedenbear cc-3 and use the throttle stop timers as an activation for the nitrous i am using 2 stages,also using 2 timers,works great
the cc-3 has 4 usable times and are relayed for 30 amps each
I was looking for the schematic for the Digi-set timers & found thier site with them. they have quite a number of them with different features. it looks like the TDM Series is the one to use for a 2nd stage of nitrous or anything that you wanted to delay the activation.