If memory serves the rules of thumb are:
1. Stall speed increase for higher weight = old speed + 1/2 % increase in weight e.g. wt inc. 20% stall speed inc. 10% therefore if old speed is 100 kts new speed is 110 kts.
2. Stall speed inc. in turn = old speed x square root of load factor e.g. in 60 degree AOB turn load factor is 2, root of 2 = 1.414, if old speed is 100 kts new speed is 141.4 kts.
3. Stall speed increases if load factor increases, decreases if load factor decreases.