Dan, you always qualifying with same amount of fuel and push level. So the only difference is the tyre compound you set up for your first stint.
As for the idea of changing fuel amount when you see your qualifying position, I don't think it's going to be much effective, as your opponents will also be able to do that.
Some stratgies work well only if you qualify in a specific area, for example, if you're way behind where you want to finish, doing a heavy first stint is never going to work because you'll lose the front running pack quickly. On the contrary, if you're on pole having a light first stint is almost never worth it because though you'll pull away, you won't have DRS so when it comes time to pit, the net result is slower.