I'm not totally certain I understand...
1st gear is with the cable pulled tight. Most people will call this "Low gear"
2nd gear is the 1:1, and is with the cable somewhere in the middle.
3rd gear is with the cable slack. Most of us call this "High gear." It's what you'd get if you removed the indicator from the hub.
There isn't a dead spot between 1st (tight cable) and 2nd (not quite as tight as first). There is the Neutral setting on the older hubs between 2nd and third. It may take a couple degrees of sprocket rotation to engage 1st from 2nd or vice versa.
Modern Sturmey hubs (the only modern one I've ridden is a 5 speed) have no dead spot between any gears.
That bike is going to be stunning, by the way. Very nice! What size tires/wheels are you using?