It's all a matter or personal preference (obviously), but if it were me, I'd ditch the electric cut-out idea. Those things are heavy and are just that much more "stuff" to possibly go wrong.
A properly set-up exhaust will not give up any power versus an open header/exhaust setup, additionally.
Even Jon Kaase discovered this on one of this Engine Masters setups.
What size are your collectors, what's the rationale behind the electric cut-outs and how far out the back were you wanting to run your tailpipes? Reason I ask all of this is because it's all pertinent.
Knowing what bit I do about your car's build (from your thread), first and foremost you're not going to be able to run full tailpipes out the back of the car (at least not in the stock location) with the suspension that's been discussed (i.e. anti-roll bar installed). I realize you don't have an AR bar installed at the moment, but ultimately it's going to help your car's suspension/chassis work a lot better. That said, installing one is going to limit your tailpipe options.
While I'm not a fan of this set-up for a street driven car (which I don't think you have any intention of doing...or, at that, in limited amounts), I'd simply run the exhaust from the headers through a cross-over pipe, through some mufflers and then run some dumps directly before the rear end housing. Reason I don't like this setup for street cars is it tends to lead to a lot of resonance in the car...which is annoying after a few minutes if it's a car you drive regularly on the street.
Also, I ask about collector size because as the exhaust travels down the exhaust path, it loses heat (dissipated out the tubes) and because it loses heat it loses velocity, as well. Granted an exhaust setup like I suggested above is not a very length exhaust (relative to a car with tailpipes all the way out the back of the car), but presuming the collectors are 3.5" in diameter, I'd probably reduce that diameter down to 3" immediately after the collector (or after the crossover section) and run it through 3" mufflers (given the dynamics of your build).
I know it sounds odd, but down the length of the exhaust, you want to reduce the diameter of the pipe to some degree depending on the engine build & displacement, length of the exhaust and the operating range of the engine. By reducing the diameter, you keep more heat in the exhaust, you keep velocity higher and both contribute to better scavenging.
If it were me, I'd ditch the electric cutouts altogether and run it through the mufflers 100% of the time, but that's me. Some guys like the open header sound.