Hey Brian.
If people need to sub the JFET, the import thing is that the drain->source resistance is low (with no voltage applied at the gate) -- you want something between 200-400R ideally, but the J201 is all the way up at 1K, and if you look at the resistor it's in parallel with, you'll see that can only has a 2.7:1 ratio, whereas something around 300 would give you a 9:1. I tend to look for 350, IIRC. I sorted them a long time ago but it's been so long since I built one.
The subs here will all be lower gain things (3819) as well as near-subs like the 5952 and BF245, all accounting for pin orientation of course.