Here are some additional thoughts:
1) You can start of your smoke on the "smoke setting." This will produce a more constant smoke at the start. You can experiment with how much time on the "smoke setting" will work best for you. I hear many people will start off for one to two hours on "smoke" and then bump up the temperature for the remainder of the cook.
2) Change to setting of the smoke stack cap. You may wish to wind it down when using lower temperatures, such as on "smoke setting," and then raise it up for higher temps. This will allow from more air flow to move throughout the chamber. If you have a vertical pellet smoker, make certain the water pan always has water in it... I hear is helps as a heat sink to regulate temps.
3) Besides a smoke tube, another thing to play around with is the wood pellet brands. Although I like PB pellets (mainly I can get them at my local Wal-Mart), I have tried several other brands including Weber and Traeger... although after reading many [bad] comments about Traeger pellets, I no longer will use them. The brand that I really like is Lumber Jack pellets--I find that this brand produces better smoke infused flavor to my cooks! I know this may be subjective, but in my opinion there is a difference. They cost a little more that PB pellets, but to me it is well worth the extra cost. My favorite pellets are Lumber Jack 100% hickey and mesquite. I do not know where you can find Lumber Jack pellets where you live, but I have found them at Dick's Sporting Goods. They can ship them to your house. Here is a link:
https://www.dickssportinggoods.com/search/SearchDisplay?categoryId=&storeId=15108&catalogId=12301&langId=-1&sType=SimpleSearch&resultCatEntryType=2&showResultsPage=true&fromPage=Search&searchSource=Q&pageView=&beginIndex=0&pageSize=48&searchTerm=lumber+jack+pellets&DSGsearchType=Keyword&advsearch=true&SearchType=Keyword&filterFacets=facetStore:ISA,SHIP
These are just some suggestions for you. I own a PB Austin XL grill and PB 5-series vertical smoker for over a year now. I love them both, and I'm still learning how to use them. I am trying to perfect a great pork butt, but still have some things to learn--that is why I watch a lot of how-to-videos on YouTube.
Blessing Again!
-Kevin