Max smoker temps

Maximum temps will depend on what you want to cook. Poultry doesn't generally benefit from low & slow, unless you're smoking tough old roasting hens, so you may want to be able to get at least 300* for birds. Some folks prefer to smoke poultry @ 325* and higher. Otherwise, 250* will suffice for beef brisket, pork shoulder cuts, ribs and other tougher cuts with a higher percentage of callogen and fat...low & slow for those @ 225-250*.

EDIT: forgot to mention, you need to take weather into consideration as well. If tested in mild temps with no wind or precipitation, you will not get peak temps that high with nasty weather, so be sure it can handle whatever mother nature will dish out.

Having a damper will depend on grate temp variances, which, with a reverse flow should be minimal, and, fuel consumption. If you have too much draft, you will burn a lot of fuel, while too little can create stale smoke and grate temp variances. It's a balancing act of sorts...you want a reasonable amount of flow for good thermal convection to cook the food, yet no so much that you use excessive amounts of fuel. If flow is too little, food cooks slower unless chamber temps are bumped up a bit, but lower flow rates can also can create excessive smoke chamber humidity from evaporated moisture in the meat. Other factors relating to the need for a damper are the diameter and height of the stake vs smoke chamber capacity, as well as a vent stack riser inside the smoke chamber (lowered vent @ grate level), or lack thereof. If you built your smoker with a specific use in mind from proven specifications, then it may work just fine for that purpose, but not for general use in a wide variety of applications. General rule of thumb is to have a damper on the vent stack so you can fine tune for the best performance and fuel efficiency...it will take some time for you to get to know your smoker, and that's true with store-bought or home-built.

Eric