I haven't added disc brakes, and the reasons are two: I don't drive fast enough to need them. I enjoy feeling safe and at any speed over 60 with stock suspension, steering, etc (including the roads we have here) I don't always get that feeling. And two...drum brakes have always stopped my truck just fine.
Before the 1952 Chevy 1/2 ton, I had a 1951 GMC with the smaller 6 and drum brakes always worked fine in that one also. As for dual master cylinder, I haven't done that either. I can see the benefit, naturally but it seems to me as long as you have a good master cylinder kept in good repair, good brake fluid changed regularly, sound brake lines and good wheel cylinders kept in good repair and sound anchor nuts, the system should be fine. Actually, it stops better than many cars I've owned and with reasonable enough pressure that my wife can drive it well. I haven't seen the need to spend the money to change. Good luck no matter which way you go.
