$15 seems very cheap for that long universal hose! I was thinking closer to $35-50! I have bought 1g caravan radiators for as little as $70 new in the past and even 'normal' replacement radiator costs are usually $100-110 when you have good pricing from vendors, so that's where my 2 universal hoses=1 new radiator idea came from. It sounds like you are pretty well set either way because the setup you built sort of prepares you for the worst case scenario as far as what kind of radiator you could get yours hands on on a road trip or something. As long as the water neck on the radiator is the same size, even if you got one with the outlet on the passenger side you could probably make your long flex hose do a full loop to hook up to it and just leave the excess laying across the intake until you found the proper fitting replacement.
The temperature idea is interesting but presumably as long as your radiator cap is functioning, the system never sees pressure beyond a certain point whether the engine is running or not. But, if the system never hits the 'blow-off' pressure while running and only hits it when heat soaking after shutdown, then yeah i guess the timer fan could keep the system from ever seeing that pressure. Interesting thing to think about.