If there's one thing we know about then it's wood chunks, back in 2012 we started ProSmoke BBQ primarily because we couldn't find American hardwoods anywhere in the UK, so we got importing. We now have a solid supply of virtually barkless kiln dried wood chunks, these guarantee a clean burn every time, giving your food that unmistakable flavour and look. 

Sizes and quantity may vary slightly per pack, but we aim to ship 2.5kg's of good fist-size chunks in a reusable cloth bag, we aim for 8 chunks. 
These chunks now are mostly barkless and fist sized, often too big for kamado smokers and the smaller webers, so get yourself a small axe to reduce the size and give you more cooks.

The pictures show just how big a chunk can be, this chunk would work great in an offset smoker, or large vertical smoker.
The second picture is one chunk chopped in half, perfect for a kettle bbq or small smoker.
The third picture is a chunk split into 4 bits, this would be my recommendation for a kamado, but the bigger the kamado the bigger you can have the chunk.
By chopping your chunks and using them as a flavour enhancer you spread your wood a lot further. 

This information has come from a professional BBQ competitor and is solid advice on how to use wood chunks:
1) Any meat would only absorb smoke through the first 2-3hr max.
2) That's on a slow cook at around 225 Fahrenheit pit temp. Grilling would reduce that window to around 10 to 15 mins.
3) I would use a lump of a stronger wood (Hickory) and same sized fruitwood (Pecan) to smoke a whole pork shoulder. Reduce the wood chunk size to suit your BBQ. 
4) If it's grilling for 'food' and not competition style cuts, a few small pieces direct over hot coal lid down would be enough to smoke for a good 30-45 mins.
Once each chunk has been halved, you have 16 chunks, which would do 8 cooks!

Hickory
This wood creates a sweet, yet strong flavour, the smoke can be pungent, but it adds a nice, strong flavour to just about all meat cuts, but it’s especially popular with pork and beef.

Pecan
This wood is stronger than most fruitwoods, but milder than hickory and mesquite. Pecan is ideal when smoking poultry and fish as it adds a bit more kick than cherry and apple, but won't over smoke.

Compressed Oak Chunks
Due to oak being a very heavy dense wood, often with lots of moister we prefer to burn it as a pure compressed wood chunk, this is made from 100% oak dust and gives a lovely light smoke.
1 chunk for mild flavouring, and 2-3 for medium to strong, you really can't go wrong with these, they burn with clean blue smoke whatever the cooker.