I prefer the square curry to the round.
If you are looking to get a good grooming kit then you are better to save and get really good quality body brusk. I have leather backed ones with natural bristle and they are still going strong after about 20 years of regular use.
You need a hoof pick, stiff brush, body brush, rubber circular curry comb, metal curry for cleaning the brushes. For a mane comb I use a metal dog comb with a handle and as I spray their tails with an anti tangle spray I also use it on their tails. You will not break the tail hair if you start combing through from the bottom of the tail.
I finish off grooming by using an old towel to take out the final dust. I do not use show sheen or anything like it on their bodies.
I only oil their feet if they are going somewhere special.