my goats all vary on which one is easiest to cut. When its wet in the winter there feet are like butter and very easy to cut. in the summer they become harder to cut as it drys up. I have read of soaking the feet in
water for a given amount of time helps soften the feet.
You could take a rasp file to the feet which are difficult.
I take my goats for quite a lot of walks in the winter which helps trim there feet down. right now i am relying on the rocks i have in there pen and my ARS Shears from japan. I also use a hoof knife. One day i will spend the money and get a really nice rasp file and most likely be cutting and using the file to smooth it out as its difficult to get a smooth surface after cutting with just the shears.