The main issue with regard to the Harrier and wing lift at low speed is the angle of attack of the wing. In a zero aispeed hover this is minus 90 deg as the engine efflux is inducing a not inconsiderable downwards flow of air all over the wing. Thus producing a negatve lift. The extent of the downwards flow over the wing will depend on the thrust in use and any slight airspeed. How this average wing AOA varies with speed also depends on the flap angle and the nozzle angle
The next thing that is likely to affect your hover preformance is the temp of the air entering the engine. A 20,000 lb class jet engine will lose about 100 lb of thrust per 1 deg C rise of intake air temperature. This may not sound much but it means 10 deg costs you 1000lb which starts to become real money. So recirculation of exhaust gases from either the far field or the near field can be of major concern and affect how you choose to operate.
LIDS effects peak at about 1400 lb up when standing on the wheels and become very small above about 8ft main wheel ground clearance. The LIDS are very beneficial on VTO because the (average) force of 700lb is aplied for several seconds during a slow go. Thanks to Mr Newton´s laws of motion this really does improve the VTO perf. A VL is quite different as the 700lbs is not applied for anything like as long because good jetmanship requires (for various reasons) a very positive rate of descent down through the ground effect layer.
I mention these non contentious issues just to show how the application of simple common sense can lead a young lad astray. The rest I will leave to the current experts because it seems to me that after a time Frank Sinatra (or any other old b***er) should refuse to climb back up on the stage and sing another song – however tempting the invitation might seem.
As to differences between RAF, RN or USMC ops, well in my experience the units have different cultures. And if they are all different ask yourself - can they all be right?