You should be targeting smaller sharks first before targeting bronzies. I.e. learn to catch hounds and spotted gulley sharks first. For this a reel with 300m of 50lb should be fine (maybe up the lb to 60-70 if there is rocks nearby). If you are targeting larger sharks you really don't know if you will hook a 50 or 150kg shark, and some days they are just more wild than others and the currents etc. make life difficult, so as Dewalds said buy a big grinder load it with 800m plus braid of at least 50lb. There is no minimum amount since you may still get smoked on heavy tackle but other days you may turn the shark quicker. 40 to 50lbs drag is fine but you will tire sooner than the shark with that drag and thus the need for capacity. Also if you put too much pressure on a bronzie from the beginning it will tend to jump and or wrap, many fish have been lost this way. For a novice I would say rather up the lb than the capacity because drifting kelp is an issue to deal with as is dealing with the shark when it comes in and the increased lb will help offset those mistakes we all made when starting to target bigger sharks. Make sure your terminal tackle is impeccable, use quality hooks, steel, swivel and leader, test all you knots properly.
What the old articles don't always mention is that the mono and thick wind on leaders had more drag which tires the sharks a bit quicker and puts less strain on the angler (well that was the experience with the transition to grinders and braid). We also used broomstick for rods and you would brake with your thumb on the spool if the shark ran too far... tight lines!
