Hi Andy, thanks for your layout, actually I build with your 1M bass pot mod from P2P layout
and it works great, I tried many jfet: 2n5457, 5484, J111, J112, 2sk161 and 163...
some of them could set at 4v bias but not one works good as J201 smd,
luckly I got fews on hand and have a good result,
I share some photo and demo here, thanks again for your great job.
Google photo:
https://photos.app.goo.gl/S8qvtyEGsPJJ3UuT9