Light loads, 2-3 medium bodies, 50ish liters of fuel, 17" prop and averaging around 20 kts I guess. That will include a reasonable amount of tick-over, waiting for lock gates to open etc. Top speed is just over 35kts but probably against wind and tide. I don't get much chance to fully open up as the sea is rarely flat enough around here. I used to get a similar, although slightly less top speed from a 75 clamshell with one on board but it ate fuel and the acceleration was poor compared to the 115. That was also 1 up, with the smaller, lighter console and smaller fuel tanks. I took 4 single tank divers out for a short trip once with the 75 and it was struggling to plane. I have no doubt that the 115 will manage with ease.
One thing worth noting is that the 530 changed at some point. Mine is the very old and very heavy hull with the vertical reverse chines and thick transom returns. It doesn't have the lip at the top of the transom. There may be a weight difference between the early and later models. I think my hull only weight is in the order of 250kg, according to the plate. It pushes 650kg without passengers or kit.