Your choice of smoker requires some heavy modification to become less than aggravating. I would seriously suggest more practice at fire and temp management before spending the big bucks on a brisket. They can be tricky and frustrating and you don't want to be disappointed and frustrated before you get the hang of smoking. . Yes raising the fire grate and using lump helps with a small hotter fire. Pure Stick Burning is a whole Art in itself and requires a Tight firebox to burn clean and efficiently. You want to start a small fire and using the air damper, control it until the desired temp is reached, Start damper wide open. When you reach temp, toss on a chunk of smoke wood and close the damper most of the way to maintain temp, opening if temp starts dropping. It is easier to make more heat than it is to choke down a huge fire. Chicken Quarters are cheap, are forgiving and good for practice. If you have to have Beef, a Chuck Roast is much cheaper and is tasty Pulled. If dry or tough, Chuck can easily be made into Chili or Taco meat.
If you are handy with tools, any offset can be made to work, the heavier the metal and construction the more efficient they are. Oklahoma Joe's are a step up and Yoder's are very nice. You may find building an Ugly Drum Smoker (UDS) is to your liking. If you want to buy a great smoker that works well out of the Box, no mods needed. The Weber Smokey Mountain (WSM) series is very popular. Then there are electrics, gassers and pellet smokers to choose from...JJ