I wouldnt tie the braid straight mostly as you'll find it hard to get a decent knot that wont slip or break really easily (stretch is another factor). Unless you have a lot of wire, best having a leader anyways (abrasion against the fish/shark and also so the lines a bit less visible as you can use less wire and have your braid further away).

10kg mono and 10kg braid should be the same breaking strain. (in practice braid is under-rated to account for knots people tend to use, so even if it actually breaks higher you wont see that unless you use very specific knots). Braid is a lot stronger for the same thickness however, so 10kg braid will be a fair bit thinner than 10kg mono and also cast better (some braids are better casting as well). So a 50lb braid might be equivalent to the same thickness 10 or 15lb mono for example.

Double your braid and tie a leader on. at least 2 rod lengths as i dont like casting with my finger on the braid. i rekon it could lead to sum nasty cuts. i use 60lb leader off the beach and 30-50lb braid, which is the about the same diameter as 10-15lb mono. so it casts like a dream. recently aquired the gt-knot. so will see how it casts.