If you have the Sports Mag or the Mag Elite, you have the magnetic control to help you cast. Slide the mags to full on to begin with (number and then decrease or increase as your abilities and conditions allow. As for the speed of drop you mentioned, this is the control of the centrifugal brake blocks. Basically, with the blocks installed, the lead shouldn't drop like a stone and allow the spool to overrun causing the birdy. It would be more of a controlled drop. This is all fine and well, but it will reduce your distance.
As for the basic casting with the mutiplier, to begin with, you need to have a good line lay on the reel. If you have a level wind on the reel, this is done for you, if you don't, then make sure the line is evenly wound onto the reel by putting the line against your thumb when reeling in and move the line slowly from side to side. Later, when you get more experienced, you can balance the reel with the line lay, but I won't go into that now. A level wind will reduce the cast length and you will find it more difficult to get a good grip on the spool with your thumb.
If you haven't cast with a multiplier before, have about 2 meters of line from the top of your rod to the lead, put your thumb firmly on the spool, release the lock to put it into free spool - still with your thumb firmly on the spool and cast. At the end of the cast, you lift your thumb and slam your thumb back on the spool when the lead touches down.
The shockleader must be a MINIMUM of 10lbs for every ounce of lead you are using as a rule. So for a 6oz lead you would use a 60lb leader. 60lb is a good all-round leader anyway - one less thing to worry about. My leaders are around 25 to 30 feet long. Don't bother measuring it out, just put the rod together, mount the reel, thread the line through the rings and tie on the leader. Wind the leader on so you have 8 turns of leader on the reel and cut the leader at least 2 meters from the end of the rod. More leader doesn't hurt by the way, but less could hurt someone else.
Just for fun, check out
http://www.longcasters.org/movielist.htm
For the techy aspects of reel tuning, check out
http://neilmackellow.sea-angler.org/reel_tuning.html
Enjoy.
Ian