Thanks, guys. These Vallejo color shifter paints are great - very easy to use and control.
I added the PE to the nozzles:

Paragraphics PE sets rarely disappoint and this was no exception - they went on nicely. The glue is still wet on these (you can see some white globs here and there). The main engines are just pressed in place. I was going to glue them in, but they're held tightly and I'm fine with the slight misalignment. The steering engines are movable. I had to slightly enlarge the holes for the bars, but they move easily:

With the "Are we there yet?" probe installed:

The color shift on the engine looks great at just the right angle.
So far, this has been a very enjoyable build - the hardest part so far has been deciding which option to build and the colors. The four large fuel tanks on the sides are meant to be dropped off after leaving Earth orbit, which would require minor surgery to the support arms; I may do it so I can add the tanks to my spares box. I then have to decide between a cargo or passenger version. The cargo version replaces the central return(?) fuel tanks in the core of the vehicle with two large cargo cylinders.
My only complaint with this kit is the wildly off size; it's almost 50% larger than the original Von Braun design (especially when compared to the 1/300 drawings in "The Spaceship Handbook")
I'll just make this an advanced heavy cargo version.