Looks pretty decent to me!
The 1969 version only has four ullage rockets, so that should decrease the amount of masking on the interstage substantially. And if the fairings fit better, that should also help. But I don't think there's any way to get away from the masking being pretty painful as long as they use the vacuform wraps.
If you zoom in on the right hand F1 engine fairing, you can see the white blotch in the middle of the black area. I was so hung up about the edges I didn't notice the tape had actually lifted in some of the middles of the black sections and got underspray on the centers of some of the black areas!!! Turns out the Peter Alway trick of a fresh black sharpie is *amazingly good* on the Rustoleum 2x Flat black paint. You have to view it in very glancing light to even notice it... even in sunlight.