One of the problems you will face in your quest is that it is impossible to tell what will work in your individual firearm until you try it. This is the most true with sabots, but also true with standard slugs. There is huge variability in this every step of the way. Some even find that this year's ammo shoots well and next year's lot doesn't work at all. Sabots just exacerbate the situation.
Your plan to buy several boxes of different stuff and try it is dead on. My advice is as soon as you find one that works, buy up as much as you can of that lot and shoot off it for several seasons. It will save you a bunch of money down the road, because you won't have to go back and redo your pre-season testing.
There was a thread on this sort of thing quite recently:
One other hint: with standard slugs it is a bit easier to find a round that works.