SpokaneDude, it's up to you what you want to use. This is like asking what will the fish bite. Frankly, they'll take anything in the right situations. All of these pattern recipes started with a tyer trying whatever material & color they had.
Soft hackles "suggest", they're not an imitation of anything specific, yet can imitate many things, so colors can be matching something they eat in the water you're fishing, or as Hatchet Jack said, a contrasting assembly of color. Some patterns are "attractors", not imitations, just something that attracts attention. Fish don't always strike a fly because they mistake it for something to eat. Actually, we can never really know for sure why they take a fly.
For most natural coloration with birds, you have limited choices. I try whatever I have on hand. With Hungarian Partridge, you get shades of brown & shades of gray, either will work fine on a soft hackle & either would be fine with a red body, or any other color you want to try.
I learned long ago that all flies will catch some fish at some time or place. I've been tying & fly fishing for 50 years. Now, I tie based on what looks good to me. I also agree with HJ about "buggy", but soft hackles really aren't supposed to be buggy.
The thing is, try different combinations, and let the fish tell you what's going to interest them.