I replied to your other thread about overcooked and dry in your other thread.
What are you getting for smoke? What you want is TBS (thin blue smoke) not billowing white smoke. TBS is light blue smoke or just a little whisp of smoke or even not seeing smoke but in all those cases you should smell the smoke. If you can smell the smoke so can the meat. White billowing smoke often leads to creosote which doesn't taste good at all usually the first clue your producing creosote is when eating the Q the flavor is off a little and it makes you tongues numb. You can also get creosote by closing the vents down or closing them to much to allow for proper draft. If you find your not getting enough smoke flavor for your tastes instead of trying to produce more smoke and getting the white billowing smoke change types of wood. Generally fruit and citrus woods produce a light somewhat fruity flavor. Then pecan and oak produce a deeper smoke flavor. Then hickory is a deeper flavor yet. If you still don't have enough try mesquite. Some people also like to mix types of woods together.
With every propane type smoker every time you open the door your loosing most of your heat and it has to get back up to temp after you close the door which if your opening it often is adding a lot of time to your smokes. Some say if your looking you ain't cooking and that comes from the fact of opening the door drops the temps so bad in the smoker.
There is debate among a lot of people as to the purpose of the "Water Pan" some will say it's there to add moisture to the smoker others will say it's a heat sync to help keep temps more even. Some say maybe some of both. Others will tell you to put sand in the pan and aluminum foil over that to keep it from getting nasty. Personally I think it's more the heat sync than anything but maybe it does provide some moisture after all your smoking above boiling point and that water vapor from the boiling water has to go somewhere like out the vent. Many people decide to fill the "water pan" with things like apple juice, beer, wine, and a host of other things thinking they will get that flavor in the meat however it doesn't work and I don't know of any of them that have come back and said they got that flavor in the meat. If you want that flavor when eating your Q I suggest you drink it while eating the Q 
 
Many of our members have found a much better way than chips or chunks to produce smoke. It's called an 
Amazen Smoker and it holds pellets which when lit produce a good amount of smoke for a long time. You would want to use the 
Amazen Smoker tube smoker in a propane smoker and for most smokes you would fill and light it at the beginning of the smoke and it would last the entire smoke.
Sorry for the novel but you asked lol by the way I first started smoking with a propane smoker and had a couple of them