Glenn May did a video on adjusting a baitcaster on YouTube and I was wondering if I was using a 3.5 ounce swimbait, should the centrifugal brake be able to be set high enough to hold that swimbait when the cast lever is pressed? I have a Daiwa Lexa 300PWR.

That wouldn't have anything to do with the brakes, and that reel has magnetic brakes not centrifugal. You would use the spool tension knob to set the lures fall rate. It's the small round knob behind the drag star. Setting it that high on a bait that heavy will hurt casting distance. It's not required.

Set spool tension to eliminate any play and turn your mag brake dial to about 3/4 of the way. Then adjust brakes as necessary until you find your sweet spot. I've never zero'd my brake dial on any of my Daiwa reels.