I've owned a 1000 coupe with A14, 120Y 4spd, 4.1 diff and 155SR12. 1st gear wasn't useless in that (3.513 vs T50 3.587 - that's less than half the % difference than 3.7 vs 3.9 diffs which you say meant squat, so this is about half of squat).

2nd gear (2.02 T50) would be stupidly tall and useless for starts. Even ~400kg race cars running lower diffs and smaller tyres than your 1000 dont go that extreme with 1st gear!