On the left side of the reel is the min, max setting you are talking about. That brake will control the high speed end of the spool spin, like mid cast for example. On the right side there is a small knob, that does the slower speed. You can not have one maxed out and other left untouched and expect it to cast correctly. They both need to be set. How i set my slow speed is put the bait on the line, press free spool the lure should drop, tighten it till it does not (give the spool a push with your thumb to try to make it fall, line will hang up somtimes messing it up what your lookin for)with the line not being able to fall keep the free spool open and loosen the knob till the bait does fall, then i snug it in a tad. (this may need to be adjusted again when your fine tuning, your ball parked here)
Well try putting the mag. brakes to max. Cast around with it. Then back them off alittle, cast somemore. Go till you fine the sweet spot for YOU. I have found with all my casting reels a setting for myself will not work well with another person. I like a loose spool and rely mostly on myself to do the thumbing, whiles others like a tight spool that has not input for them selfs.
I almost never,have to adjust my reels once i have them set to my likeing. Some may disagree, but i have found a setting i like. And i work around that, say if you throw a spinner bait 90% of the time set it up for that and then you adjust yourself when not using a spinnerbait.
A casting reel will become secound nature and once you become intune with whats happening your unstopable.
BTW you got a great reel on your hands, dont let it frustrate you. Take the time, figure it out. It will give you many many years of great service.