Use second gear. I have a '96NA, and first gear can't perform a roll-start, but it catches just fine in second. I have no idea why that is, but I remember I was just about of hill when I discovered it.

It's because the wheels can turn the engine more easily and for longer in higher gears. This isn't intuitive until you realize that you've flipped the inputs and outputs of the transmission, and this inverts the gearing relationship. _Higher_ gears are better at multiplying relatively little input (wheelspin) into a lot of output (engine rotation).

You learn the same lesson (2nd gear starts) with motorcycles, which have much smaller batteries and fragile charging systems so the need to push-start is unfortunately common.