Depends what your using, if using bait I'd go a 6000 size real with a 6-10kg rod with 30lb braid and 30-50lb leader to play it safe invade a big hoodlum comes along. If using plastics and other lures go for a 3-6 kg rod and the 4000 sienna sounds great. The problem with using 10kg line is you won't be able to fit that much onto the spool. Try 10-16lb line which will mean more line, better casting but still enough strenght (if fought well) to land a sizable king. Good Luck mate and I hope I helped.
Tight lines
Jennings