6371 lbs is full fuel on a Sea King 3/3A but you do have to strip out some of the role kit to keep within the 21,400 MAUM. The Vmax starts off low at that weight (105 kts) but quickly increases giving an average speed over a 4 to 5 hour long-range rescue of about 110 kts.
Our standard planning has 30 min on scene, a min landing fuel of 400 lbs and a 10% reserve for contingency and the aircraft will typically land with 1000 lbs.
As far as the S92 goes, perhaps Lala is thinking of when the S92 was originally introduced in Stornoway and Sumburgh without the bigger tanks fitted as standard.