> you can swap out the 4148 for a 914 in MOST applications...
I remember when the 4148 was the "improved" 914, and cost more.
As bcarso says, today any diode costs less than a grain of rice, so they probably don't make 914 parts any more, just the 4148 part.
I'm not sure the 60V spec on 914 was ever "real". Back when there were "real" 914s cheaper than 4148, I needed some 80V-90V Zeners. I had heaps of 914s. I started testing then for Reverse Breakdown: at 0.5mA, they all zenered at 110V to 130V. OK, maybe the leakage rose at 60V, I didn't test that. But the uniformity told me they were doped for 100V +20% safety factor, even though sold as 60V parts.
I don't see where any of the GSSL's diodes sees even 10V reverse voltage (some less than 1V), or where a microamp of leakage would bother anything. You can use about any hunk of silicon. If you happened to have a sack of transistors in hand, you could use their C-B junctions.