I had good luck with Federal Flite Control 2oz lead fives out of a factory full in a few guns. 3.5" Heavyweight #5s held a pattern a long way out of factory full 835.
If you get into TSS factory full might be too tight for a hunting pattern.
One thing worth considering is that not all factory chokes are equal. A budget gun with a cheap, basic short choke system is not likely to throw as good a factory flush choke pattern as a better gun with longer, well-designed internal chokes. You'll have to pay up for an aftermarket extended choke to get the say performance. Chokes can be part of what makes better guns more expensive. A good set of factory chokes adds a lot of value to a gun.