As a latecomer to the thread and also someone who's "nailed colours to the mast" and gone for rear discs, even so I'm intrigued by the idea of a device which slightly delays the front brake onset. It's not something I've come across before but if it's a standard fitment on US cars with Disc/Drums then I'm surprised it's not made it to the UK. (maybe it has, and I've just missed it ? )
A residual pressure valve in the rear line should have a similar effect because it keeps the drums just on the point of activation with (I think) a 10psi line pressure. Valves for discs are lower, 2psi on the ones I used.
I'm normally a fan of Golden Gate articles but that one is misleading, or at least it is if you skim it quickly like I've just done. Elan front brakes for the 2 seater are pretty much the same as the Europa, it was the heavier +2 which has larger calipers/discs. The calipers aren't "similar but mounted further out" either, the Type 16 caliper has not only different mounting points but larger pistons, larger pads and is way, way heavier.
However the Elan with knock-on wheels does have the heavier vertical links so is easy to fit the larger discs/calipers, and I've done it.
Still on the article, I also thought the S1/S2/TC all had the smaller rear drum widths with only the TCS going to 1.5", it seems illogical that Lotus would fit smaller brakes on the heavier TC after several years on the S1/S2. But I've never owned an S2 so is this something else that I've misunderstood over the years ?
Finally a potentially controversial comment. I know the Road tests of the day praised the Europa brakes and we all know they work really well as standard in dry conditions if you think and apply the pedal with weight transfer in mind.
But that's something we've adapted to and if you tried to market a performance car with similar braking characteristics today then I think you'd lose. The designer thinks "the average Joe is going to stab hard on the brakes when he panics, so let's design the problem out", hence we have balanced systems and ABS these days.
Personally I'd prefer not to rely on my skill (?) to prevent lock up on a wet road when something unexpected happens in front. So if adding the device you've referred to, or a residual pressure valve to the rear lines makes it safer in that rare moment when your brain screams "stop !!!" and you forget all about gentle pressure first, then I'd go for it !
Brian