When transitioning to the hover, are nozzles rotated to vertical and then airspeed left to wash off, while engine rpm is gradually increased to counter the effect of the unloading of the wings?
Yes, that's right. Nozzles are usually rotated in 2 chunks - 40 degrees selected downwind, then hover-stop (approx 80 deg as the jet sits 8 or 9 deg nose up in the landing attitude) at the deceleration point which is about half a mile from the desired landing spot. The pilot will be flying 10 alpha until the hover-stop is selected; he will then keep the jet level with increasing power as the wing lift gradually reduces. Below about 45kts the aircraft will be pretty much wholly jet-borne.
Fore and aft speed can be controlled in the deceleration and hover by pitch, although nozzle movements are generally used if more than 5 deg NU/ND is required.
Similarly, when transitioning out of hover, increase power and rotate nozzles slowly back as wings develop lift?
Exactly that. From the hover, add some power, pitch up a couple of degrees then nozzle out. The rate of nozzle movement depends on how much excess power is available.
Getting in and out of the hover is the trickiest part of VSTOL ops. In a steady hover the jet is pretty well balanced and flies like a sluggish helicopter. The transition can be tricky as all the variables are constantly changing. Keeping the aircraft in balance is of paramount importance, as Intake Momentum Drag can flip a jet over in fairly short order. I'll let a QFI explain that one........
Hope this helps