Prop Valve Location

I'm going with Wilwood's front & rear disc brake conversion and master cylinder. Should the proportioning valve go before or after the distribution block/safety switch? I like Wilwood's master cylinder with the prop valve attached. However, my concern is that having the prop valve before the distribution block/safety switch will affect the front/rear brake pressure and will trigger the safety switch...and thus my dashboard warning light which I'd like to avoid. Where do you guys place your prop valves?

Thanks,
Eric