Personally you would have to refer to what usually works where you will be fishing. I know you can buy half capes from whitings that will allow you to tie down past 24 sometimes into 30!!! But then again the majority of feathers will not be in your 24 range.... yet again you dont need much hackle on a size 24 hook.

Yes capes from whitings.. in my experience have feathers that small. Although it would be much cheaper for you to buy the flies in various colours and sizes.

I do not know where you are fishing and what the colour the fish like. But I like to follow the old addage, on a dark day a dark fly and on a light day a lighter fly... although this can be proven wrong many times over.

I tend to use natural colours like dun and black and brown mostly. Sometimes a ginger colour. I personally do not use badger very much at all.

That is just my two cents.