Can I make them today for a Saturday party or will they have that left on a buffet all day long taste to them?
I think that depending on the recipe you could possibly get them halfway ready and do a last minute finishing up fry on Saturday. That said, I'm not sure how much time you'll actually save doing that so it might just make more sense to bite the bullet and make them Saturday. Also, YUM homefries...
You can certainly blanch your potatoes a day ahead (maybe even two), but there's no good way to get around the frying on the day of. But if you saute your potatoes in a big cast iron skillet on low heat and turn them every few minutes, you'll get a nice even browning without having to stand over the pan waiting for the magic to happen. Sometimes patience works best!
I agree with blanching/parcooking the potato chunks today and doing the actual cooking day of. I suppose you could cook them a few days ahead, but their flavor will be severely diminished on the day of consumption.