Terry.....your 7 day load is over 180 TSS/day with pretty high intensity? What is your TSB and CTL? You mention frequently your concern about overtraining. If your FTP is set correctly, this is a very, very high load. Not saying it is too high because I have been there and higher myself. But I'd say your playing with fire, if FTP is correct.

As to Zone 4, I tend to do them just over FTP and for 8-10 minutes on a certain climb. But rarely do those but sometimes.