I'd drop back to about 15lb test mono on that reel, for a couple reasons. First of all, you don't have enough line capacity with it spooled with 20lb test. Secondly, you'd get more line on it if you went with braid, but you'd lose any advantage because the drag & gears in that reel can't handle a higher test line, especially one with no stretch or forgiveness. It is after all only a $30.00-$40.00 reel,,, to push it beyond it's limits is asking for trouble.
With 15lb test mono, you'll have a bit more line on the reel, and the forgiving stretch of mono to ease the stress on the gears. Just make sure if you're fishing from a pier that you have a net long enough to reach the water.