I did a simulation of the clamp and it clamps at 5v, both polarities which is under the 6v reverse breakdown so the thing shouldn't get zenered. It's a bit tight though!
As for the JFET pricing, it's reasonable from Mouser but it's ?15 delivery (what I paid for the meter) or min spend. I have a shopping list a mile long so it might be used to bulk an order up. I'll do some thinking. I will most likely throw a 3904 in there soon, at least from the perspective of the experimental side of this and then replace it with a JFET later.
