Ah, hadn't thought of that. Nice tie.

Again, there's no reason the tailing packs wouldn't work because they are roughly the equivalent of the Spanish feathers. For soft hackles, the Whiting CDL rooster cape or saddle would probably be a better bet. From the picture I'd say you need a "medium pardo" colored saddle (or maybe even "dark pardo") . Neither the capes nor the saddles are all that expensive ($20-$30 I think). Stone River Outfitters (sponsor's page) carries the saddles and can probably get the capes for you.

You may want to see if you can find some of the CDL hen saddles for soft hackles, however. The rooster feathers make great tails but would be too stiff, for me anyway, for soft hackles. The hen saddles are more like partridge although the range of the feathers is not as good. The colors are different, however, so if you are looking for the exact same effect, you'll have to stick with rooster.

Luck.