Gene, I have oem HB on a 1 ton Chevy for the last 25 years or so.
The empty vehicle weight is over twice that of the vette and even when new the 1 ton had and still does have a little spongy feel to the pedal. Even when you lock them all up you can go further with the pedal, not as mushy as a stock pb vette but similar to other modern vehicle pb.
On a Vette, the HB is just grossly overpowering, I assume due to the weight difference. Did a setup on a vette a few years ago, so am familiar. I'm not knocking the HB on a vette, but just want a simpler route with a wider range of modulation.
The best brakes I've found outside of Mercedes has been on my wife's Caravan, oem 4 wheel disc setup (not too common). Free pedal travel is about 1/2", then pretty firm, with a little bit of sponge, with lockup at less than 2". There is still some sponge left in the pedal, can force it down another 1-1/2" for no gain.
IMO, it is at least as good or better than HB in the 1 ton. Very easy to modulate.
Copying that is really my goal.
Also have a HD 3/4 ton van which has oem 1 ton booster brakes.
This has a very spongy pedal, but activates at approx 1" down and will throw you into the windshield, and also the pedal will go down much further than needed. Very similar to oem vette pedal with less travel.
The stock vette booster has approx 1/2" of free play at first, probably to open the control valve (atmosphere) and then you have the movement in the master to move the seal past the compensating ports of about another 1/2" at the pedal. This play, you can't get rid of.
Newer vehicles just seem to have the booster and hydraulic system more accurately matched than the old GM.