OK, I will see if I have the parts to try it as well.PC1966: I had another try with Rc = 1kR and Re = 4.7kR, 10kR and 22kR over a range of voltages from 3-15V. Not a twitter at 20MHz. I also tried two other crystals.
Next I will try keeping Re at 4.7kR and reducing Rc but at the moment it is too hot in my shed to do so.
At one point we had loads of stuff for this sort of experiment but sadly it was thrown out when my last work ended. We saved some stuff "just in case" but space did not permit all of the items I wish we had kept.