*minor spoilers sorta*
I expect that, since the Supremacy was the ship with the hyperspace tracker equipped, its navicomputer would perform the calculations and then transmit the them (or just the destination, and allow the others to calculate a route) to the other ships. Its size shouldn’t really make a difference, no ship would exit hyperspace close enough to a celestial body that a bigger ship following the same route could hit it. If the navicomputer and hyperdrive are both in working order, a hyperspace jump is usually relatively safe.
~ Jacen