The GR.7 had 90 seconds of demineralised water to use for the hovver, after that then you'll start to damage the engine. Normal return to base was with two fuel tanks, although a rolling vertical landing was more usual with a heavier jet and some jets performed better than others. Most jets had different size leading edge root extensions fitted (LERX) which made a difference to performance. Very unusual/almost unheard of for a Harrier to hovver land with a heavy load out, especially if they were anywhere hot/high. If heavy they'd do a conventional landing, and in an emergency a straight in fix throttle approach seemed to be the norm. Hope that helps a bit?