In my experience wood chunks work best. I like chunks that are 4” to 5” long x 2” (approx) x
You don’t need a lot of wood to obtain a nice smoke flavor. I have a small Brinkman Smoker on the patio and when using Apple wood, I typically use 4 to 6 chunks to start. After about 2.5 hours I had 2 to 4 more and that usually is sufficient for a 4.5 to 5.5 hour smoking duration (and there is a lot of smoke produced). Of course more wood produces a stronger flavor and less wood provides a milder flavor. You will need to experiment with the amount of wood and type of wood to achieve your desired smoke flavor.
Most fruit and nut trees make good smoking woods. Never use any treated woods, pine or other woods with sap (resinous woods) like cedar or fir. These will produce, shall we say, a “terrible” flavor.